View source for Polio vaccine

{{Short description|Vaccine to prevent poliomyelitis}}
{{Use dmy dates|date=July 2024}}
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{{Good article}}
{{Infobox drug
| type = vaccine
| image = Poliodrops.jpg
| alt = 

<!-- Vaccine data -->
| target = [[Poliomyelitis]]
| vaccine_type = IPV: inactivated<br/>OPV: attenuated<br/>nOPV2: attenuated, genetically stabilised

<!-- Clinical data -->
| tradename = Ipol, Poliovax, others
| Drugs.com = {{drugs.com|monograph|poliovirus-vaccine-inactivated}}
| MedlinePlus = a601177
| DailyMedID = Ipol
| pregnancy_AU = B2
| pregnancy_AU_comment = <ref name="Drugs.com pregnancy">{{drugs.com|pregnancy|poliovirus-vaccine-inactivated}}</ref>
| pregnancy_category = 
| routes_of_administration = IPV: [[parenteral]]<br/>OPV: [[oral administration|oral]]
| ATC_prefix = J07
| ATC_suffix = BF01
| ATC_supplemental = {{ATC|J07|BF02}} {{ATC|J07|BF03}} {{ATC|J07|BF04}}

<!-- Legal status -->
| legal_AU = <!-- S2, S3, S4, S5, S6, S7, S8, S9 or Unscheduled -->
| legal_AU_comment = 
| legal_BR = <!-- OTC, A1, A2, A3, B1, B2, C1, C2, C3, C5, D1, D2, E, F1, F2, F3, F4 -->
| legal_BR_comment = 
| legal_CA = <!-- OTC, Rx-only, Schedule I, II, III, IV, V, VI, VII, VIII -->
| legal_CA_comment = 
| legal_DE = <!-- Anlage I, II, III or Unscheduled -->
| legal_DE_comment = 
| legal_NZ = <!-- Class A, B, C -->
| legal_NZ_comment = 
| legal_UK = <!-- GSL, P, POM, CD, CD Lic, CD POM, CD No Reg POM, CD (Benz) POM, CD (Anab) POM or CD Inv POM / Class A, B, C -->
| legal_UK_comment = 
| legal_US = Rx-only
| legal_US_comment = <ref>{{cite web | title=Ipol (poliovirus type 1 antigen) (formaldehyde inactivated), poliovirus type 2 antigen (formaldehyde inactivated), and poliovirus type 3 antigen- formaldehyde inactivated injection, suspension | website=DailyMed | date=2 April 2025 | url=https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=34a647f5-8728-451b-b918-94c8acd15974 | access-date=8 November 2025}}</ref><ref>{{cite web | title=Ipol – Poliovirus Vaccine Inactivated (Monkey Kidney Cell) | website=U.S. [[Food and Drug Administration]] (FDA) | date=11 December 2019 | url=https://www.fda.gov/vaccines-blood-biologics/vaccines/ipol-poliovirus-vaccine-inactivated-monkey-kidney-cell | archive-url=https://web.archive.org/web/20191223053005/https://www.fda.gov/vaccines-blood-biologics/vaccines/ipol-poliovirus-vaccine-inactivated-monkey-kidney-cell | url-status=dead | archive-date=23 December 2019 | id=STN: 103930 }}</ref>
<ref>{{cite web | title=Routine Polio Vaccination | website=U.S. [[Centers for Disease Control and Prevention]] (CDC) | date=11 May 2018 | url=https://www.cdc.gov/vaccines/vpd/polio/hcp/routine-polio-vaccination.html | access-date=8 November 2025}}</ref>
| legal_EU = 
| legal_EU_comment = 
| legal_UN = <!-- N I, II, III, IV / P I, II, III, IV -->
| legal_UN_comment = 
| legal_status = <!-- For countries not listed above -->

<!-- Identifiers -->
| CAS_number = 1008119-78-5
| PubChem = 
| IUPHAR_ligand = 
| DrugBank = DB10796
| DrugBank2 = DB10797
| ChemSpiderID = None
| UNII = 
| KEGG = D05543
| ChEBI = 
| ChEMBL = 
| NIAID_ChemDB = 
}}

<!-- Definition and medical uses -->
'''Polio vaccine''' is a [[vaccine]] used to prevent [[poliomyelitis]] (polio).<ref name=WHO2016/><ref name=WHO2022>{{cite journal | vauthors = ((World Health Organization)) | title = Polio vaccines: WHO position paper – June 2022 | journal = Weekly Epidemiological Record | volume = 97 | issue = 25 | pages = 277–300 | date = 2022 | hdl=10665/357168 | hdl-access = free | author-link = World Health Organization }}</ref> Two types are used: an [[inactivated vaccine|inactivated]] poliovirus given by injection (IPV) and a [[attenuated vaccine|weakened]] poliovirus given by mouth (OPV).<ref name=WHO2016/> The [[World Health Organization]] (WHO) recommends all children be fully vaccinated against polio.<ref name=WHO2016/> The two vaccines have eliminated polio from most of the world,<ref name="Aylward_2006">{{cite journal|vauthors=Aylward RB|year=2006|title=Eradicating polio: today's challenges and tomorrow's legacy|journal=Annals of Tropical Medicine and Parasitology|volume=100|issue=5–6|pages=401–413|doi=10.1179/136485906X97354|pmid=16899145|s2cid=25327986}}</ref><ref>{{cite journal|vauthors=Schonberger LB, Kaplan J, Kim-Farley R, Moore M, Eddins DL, Hatch M|year=1984|title=Control of paralytic poliomyelitis in the United States|journal=Reviews of Infectious Diseases|volume=6 | issue = Suppl 2|pages=S424–S426|doi=10.1093/clinids/6.Supplement_2.S424|pmid=6740085|doi-access=free}}</ref> and reduced the number of cases reported each year from an estimated 350,000 in 1988 to 33 in 2018.<ref name="gwp2013">{{cite web|url=http://polioeradication.org/wp-content/uploads/2019/02/global-wild-poliovirus-2013-2018-20190201.pdf|title=Global Wild Poliovirus 2014–2019|access-date=3 February 2019|archive-date=3 February 2019|archive-url=https://web.archive.org/web/20190203085212/http://polioeradication.org/wp-content/uploads/2019/02/global-wild-poliovirus-2013-2018-20190201.pdf|url-status=live}}</ref><ref>{{Cite web|url=https://www.who.int/features/qa/07/en/|title=Does polio still exist? Is it curable?|website=[[World Health Organization]] (WHO)|access-date=21 May 2018|archive-date=29 May 2018|archive-url=https://web.archive.org/web/20180529121019/http://www.who.int/features/qa/07/en/|url-status=live}}</ref>

<!-- Safety -->
The inactivated polio vaccines are very safe.<ref name=WHO2016/> Mild redness or pain may occur at the site of injection.<ref name=WHO2016/> Oral polio vaccines cause about three cases of vaccine-associated paralytic poliomyelitis per million doses given.<ref name=WHO2016/> This compares with 5,000 cases per million who are paralysed following a polio infection.<ref name="WHO2017Fs114">{{Cite web|url=https://www.who.int/mediacentre/factsheets/fs114/en/|title=Poliomyelitis|website=[[World Health Organization]] (WHO)|archive-url=https://web.archive.org/web/20170418105535/http://www.who.int/mediacentre/factsheets/fs114/en/|archive-date=18 April 2017|url-status = live|access-date=25 April 2017}}</ref> Both types of vaccine are generally safe to give during [[pregnancy]] and in those who have [[HIV/AIDS]], but are otherwise well.<ref name=WHO2016>{{cite journal | vauthors = ((World Health Organization)) | title = Polio vaccines: WHO position paper – March, 2016 | journal = Weekly Epidemiological Record | volume = 91 | issue = 12 | pages = 145–68 | date = 2016 | pmid = 27039410 | hdl=10665/254399 | hdl-access = free }}</ref> However, the emergence of circulating vaccine-derived poliovirus (cVDPV), a form of the vaccine virus that has reverted to causing poliomyelitis, has led to the development of novel oral polio vaccine type 2 (nOPV2), which aims to make the vaccine safer and thus stop further outbreaks of cVDPV.<ref name="GPEI-nOPV2">{{Cite web|title=GPEI-nOPV2|url=https://polioeradication.org/nopv2/|access-date=1 August 2021|archive-date=27 July 2021|archive-url=https://web.archive.org/web/20210727211943/https://polioeradication.org/nopv2/|url-status=live}}</ref>

<!-- History, society and culture -->
The first successful demonstration of a polio vaccine was by [[Hilary Koprowski]] in 1950, with a live [[Attenuated vaccine|attenuated virus]] that people drank.<ref name="Kowproski_obit">{{cite web | vauthors = Fox M | url = https://www.nytimes.com/2013/04/21/us/hilary-koprowski-developed-live-virus-polio-vaccine-dies-at-96.html | title = Hilary Koprowski, Who Developed First Live-Virus Polio Vaccine, Dies at 96 | work = [[The New York Times]] | date = 20 April 2013 | access-date = 8 September 2017 | archive-date = 25 August 2017 | archive-url = https://web.archive.org/web/20170825133630/http://www.nytimes.com/2013/04/21/us/hilary-koprowski-developed-live-virus-polio-vaccine-dies-at-96.html | url-status = live }}</ref> The vaccine was not approved for use in the United States, but was used successfully elsewhere.<ref name="Kowproski_obit"/> The success of an [[Inactivated vaccine|inactivated]] (killed) polio vaccine, developed by [[Jonas Salk]], was [[Announcement of Polio vaccine success|announced in 1955]].<ref name=WHO2016/><ref>{{cite book| vauthors = Bazin H |title=Vaccination: A History|date=2011|publisher=John Libbey Eurotext|isbn=978-2742007752|page=395|url=https://books.google.com/books?id=orjaA_7sYZQC&pg=PA395|url-status = live|archive-url=https://web.archive.org/web/20170908183608/https://books.google.com/books?id=orjaA_7sYZQC&pg=PA395|archive-date=8 September 2017}}</ref> Another attenuated live oral polio vaccine, developed by [[Albert Sabin]], came into commercial use in 1961.<ref name=WHO2016/><ref>{{cite journal|vauthors=Smith DR, Leggat PA|date=2005|title=Pioneering figures in medicine: Albert Bruce Sabin – inventor of the oral polio vaccine|journal=The Kurume Medical Journal|volume=52|issue=3|pages=111–116|doi=10.2739/kurumemedj.52.111|pmid=16422178|doi-access=free}}</ref>

Polio vaccine is on the [[WHO Model List of Essential Medicines|World Health Organization's List of Essential Medicines]].<ref name="WHO24th">{{cite book | vauthors = ((World Health Organization)) | title = The selection and use of essential medicines, 2025: WHO Model List of Essential Medicines, 24th list | year = 2025 | hdl = 10665/382243 | author-link = World Health Organization | publisher = World Health Organization | location = Geneva | hdl-access = free | doi = 10.2471/B09474 | doi-access = free | id = License: CC BY-NC-SA 3.0 IGO }}</ref>

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==Medical uses==
[[File:Polio vaccine poster.jpg|thumb|This 1963 poster featured the United States [[Centers for Disease Control and Prevention]]'s national symbol of [[public health]], the "[[Wellbee]]", encouraging the public to receive an oral polio vaccine.]]

Interruption of person-to-person transmission of the virus by vaccination is important in global [[Poliomyelitis eradication|polio eradication]],<ref name="Fine">{{cite journal|vauthors=Fine PE, Carneiro IA|date=November 1999|title=Transmissibility and persistence of oral polio vaccine viruses: implications for the global poliomyelitis eradication initiative|journal=American Journal of Epidemiology|volume=150|issue=10|pages=1001–1021|doi=10.1093/oxfordjournals.aje.a009924|pmid=10568615|doi-access=free}}</ref> since no long-term [[asymptomatic carrier|carrier]] state exists for [[poliovirus]] in individuals with normal immune function, polio viruses have no non-primate reservoir in nature,<ref>{{cite journal|vauthors=Koike S, Taya C, Kurata T, Abe S, Ise I, Yonekawa H, Nomoto A|date=February 1991|title=Transgenic mice susceptible to poliovirus|journal=Proc. Natl. Acad. Sci. U.S.A.|volume=88|issue=3|pages=951–955|bibcode=1991PNAS...88..951K|doi=10.1073/pnas.88.3.951|pmc=50932|pmid=1846972|doi-access=free}}</ref> and survival of the virus in the environment for an extended period appears to be remote. The two types of vaccine are inactivated polio vaccine (IPV) and oral polio vaccine (OPV).

===Inactivated===
When the IPV (injection) is used, 90% or more of individuals develop protective antibodies to all three [[serotype]]s of poliovirus after two doses, and at least 99% are immune following three doses. The duration of immunity induced by IPV is not known with certainty, although a complete series is thought to protect for many years.<ref name=Robertson_1993>{{cite book | vauthors = Robertson S | title = Module 6: Poliomyelitis | series = The Immunological Basis for Immunization Series | publisher = [[World Health Organization]] (WHO) | url = https://www.who.int/ihr/polio1993en.pdf | access-date = 18 October 2019 |archive-url=https://web.archive.org/web/20191019064736/https://www.who.int/ihr/polio1993en.pdf |archive-date=19 October 2019 | id = WHO/EPI/GEN/93.16 }}</ref> IPV replaced the oral vaccine in many developed countries in the 1990s mainly due to the (small) risk of vaccine-derived polio in the oral vaccine.<ref>{{Cite web|author=Public Health Agency of Canada|date=18 July 2007|title=Poliomyelitis vaccine: Canadian Immunization Guide|url=https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-17-poliomyelitis-vaccine.html|access-date=1 August 2021|website=www.canada.ca|archive-date=27 July 2021|archive-url=https://web.archive.org/web/20210727212739/https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-17-poliomyelitis-vaccine.html|url-status=live}}</ref><ref>{{Cite web|date=25 March 2021|title=Polio Vaccination: What Everyone Should Know {{!}} CDC|url=https://www.cdc.gov/vaccines/vpd/polio/public/index.html|access-date=1 August 2021|website=U.S. [[Centers for Disease Control and Prevention]] (CDC)|archive-date=16 January 2021|archive-url=https://web.archive.org/web/20210116130844/https://www.cdc.gov/vaccines/vpd/polio/public/index.html|url-status=live}}</ref>

===Attenuated===
Oral polio vaccines were easier to administer than IPV, as they eliminated the need for sterile syringes, so were more suitable for mass vaccination campaigns. OPV also provided longer-lasting [[immunity (medical)|immunity]] than the Salk vaccine, as it provides both [[humoral immunity]] and [[cell-mediated immunity]].<ref name="ReferenceZ">{{cite journal|vauthors=Wahid R, Cannon MJ, Chow M|date=May 2005|title=Virus-Specific CD4+ and CD8+ Cytotoxic T-Cell Responses and Long-Term T-Cell Memory in Individuals Vaccinated against Polio|journal=Journal of Virology|volume=79|issue=10|pages=5988–5995|doi=10.1128/JVI.79.10.5988-5995.2005|pmc=1091702|pmid=15857985}}</ref>

One dose of trivalent OPV produces immunity to all three poliovirus serotypes in roughly 50% of recipients.<ref name=PinkPages/> Three doses of live-attenuated OPV produce protective antibodies to all three poliovirus types in more than 95% of recipients. As with other live-virus vaccines, immunity initiated by OPV is probably lifelong.<ref name="Robertson_1993" /> OPV produces excellent immunity in the [[intestine]], the primary site of wild poliovirus entry, which helps prevent infection with wild virus in areas where the virus is [[endemic (epidemiology)|endemic]].<ref name=Peds/> OPV does not require special medical equipment or extensive training. Attenuated poliovirus derived from the OPV is excreted for a few days after vaccination, potentially infecting and thus indirectly inducing [[Contact immunity|immunity]] in unvaccinated individuals, thus amplifying the effects of the doses delivered.<ref name="Nathan">{{cite journal |vauthors=Nathanson N, Martin JR |date=December 1979 |title=The epidemiology of poliomyelitis: enigmas surrounding its appearance, epidemicity, and disappearance |journal=American Journal of Epidemiology |volume=110 |issue=6 |pages=672–692 |doi=10.1093/oxfordjournals.aje.a112848 |pmid=400274}}</ref> Taken together, these advantages have made it the favored vaccine of many countries, and it has long been preferred by the global eradication initiative.<ref name="GPEI-OPV">{{cite web |title=OPV - Oral Polio Vaccine |url=https://polioeradication.org/polio-today/polio-prevention/the-vaccines/opv/ |access-date=9 August 2024 |website=Global Polio Eradication Initiative (GPEI) |publisher=|url-status= dead|archive-url=https://web.archive.org/web/20240624025228/https://polioeradication.org/polio-today/polio-prevention/the-vaccines/opv/|archive-date = 24 June 2024}}</ref>[[File:Number of cVDPV cases.svg|thumb|upright=1.3|cVDPV cases (red line) outnumbered wild polio cases (blue line) for the first time in 2017]]
The primary disadvantage of OPV derives from its inherent nature. As an attenuated but active virus, it can induce vaccine-associated paralytic poliomyelitis (VAPP) in roughly one individual per every 2.7{{nbsp}}million doses administered.<ref name="GPEI-OPV" /> The live virus can circulate in under-vaccinated populations (termed either '''variant poliovirus''' or '''circulating vaccine-derived poliovirus''', cVDPV), and over time can revert to a neurovirulent form causing paralytic polio.<ref name="GPEI-OPV" /> This genetic reversal of the pathogen to a virulent form takes a considerable time and does not affect the person who was originally vaccinated. With wild polio cases at record lows, 2017 was the first year where more cases of cVDPV were recorded than the wild poliovirus.<ref>{{Cite web |title=Eradication of polio – Is Syria being left behind? |url=https://sphcm.med.unsw.edu.au/infectious-diseases-blog/eradication-polio-syria-being-left-behind |url-status=live |archive-url=https://web.archive.org/web/20181006114450/https://sphcm.med.unsw.edu.au/infectious-diseases-blog/eradication-polio-syria-being-left-behindd |archive-date=6 October 2018 |access-date=6 October 2018 |website=UNSW School of Public Health and Community Medicine |vauthors=Kunasekaran M}}</ref>

Until recent times, a trivalent OPV containing all three viral strains was used, and had nearly eradicated polio infection worldwide.<ref name="ReferenceA">{{cite journal |vauthors=Marin M, Patel M, Oberste S, Pallansch MA |date=January 2017 |title=Guidance for Assessment of Poliovirus Vaccination Status and Vaccination of Children Who Have Received Poliovirus Vaccine Outside the United States |journal=MMWR. Morbidity and Mortality Weekly Report |volume=66 |issue=1 |pages=23–25 |doi=10.15585/mmwr.mm6601a6 |pmc=5687270 |pmid=28081056 | url=https://www.cdc.gov/mmwr/volumes/66/wr/pdfs/mm6601.pdf }}</ref> With the complete eradication of wild poliovirus type{{nbsp}}2<ref>{{cite web |date=22 July 2019 |title=Poliomyelitis |url=https://www.who.int/news-room/fact-sheets/detail/poliomyelitis |url-status=live |archive-url=https://web.archive.org/web/20191017233318/https://www.who.int/news-room/fact-sheets/detail/poliomyelitis |archive-date=17 October 2019 |access-date=18 October 2019 |website=[[World Health Organization]] (WHO)}}</ref> this was phased out in 2016 and replaced with bivalent vaccine containing just types 1 and 3, supplemented with monovalent type{{nbsp}}2 OPV in regions where cVDPV type 2 was known to circulate.<ref name="GPEI-OPV" /> The switch to the bivalent vaccine and associated missing immunity against type 2 strains, among other factors, led to outbreaks of circulating vaccine-derived poliovirus type 2 (cVDPV2), which increased from two cases in 2016 to 1037 cases in 2020.<ref>{{Cite web |title=GPEI Strategy for the Response to cVDPV2 2020–2021 |url=https://polioeradication.org/wp-content/uploads/2021/03/GPEI-cVDPV2-nOPV2-Factsheet-20210312-EN.pdf |url-status=live |archive-url=https://web.archive.org/web/20210801223541/https://polioeradication.org/wp-content/uploads/2021/03/GPEI-cVDPV2-nOPV2-Factsheet-20210312-EN.pdf |archive-date=1 August 2021 |access-date=1 August 2021 |website=Polio Global Eradication Initiative}}</ref>

A novel OPV2 vaccine (nOPV2), which has been genetically modified to reduce the likelihood of disease-causing activating mutations, was granted emergency licencing in 2021, and subsequently full licensure in December 2023.<ref name=":x22">{{Cite web |date=12 April 2024 |title=GPEI-OPV Oral polio vaccine |url=https://polioeradication.org/polio-today/polio-prevention/the-vaccines/opv/ |access-date=12 April 2024 |website=Global Polio Eradication Initiative - World Health Organization }}</ref> This has greater genetic stability than the traditional oral vaccine and is less likely to revert to a virulent form.<ref name=":x2">{{Cite web |date=12 April 2024 |title=GPEI-OPV Oral polio vaccine |url=https://polioeradication.org/polio-today/polio-prevention/the-vaccines/opv/ |access-date=12 April 2024 |website=Global Polio Eradication Initiative - World Health Organization }}</ref><ref name="GPEI-nOPV2" /> Genetically stabilised vaccines targeting poliovirus types 1 and 3 are in development, with the intention that these will eventually completely replace the Sabin vaccines.<ref>{{Cite web |last=Gadye |first=Levi |date=2023-06-14 |title=Two New Vaccines Join the Fight to Eradicate Polio {{!}} UC San Francisco |url=https://www.ucsf.edu/news/2023/06/425601/two-new-vaccines-join-fight-eradicate-polio |access-date=2024-08-10 |website=The University of California San Francisco }}</ref>

===Schedule===
[[File:Share of one-year-olds vaccinated against polio (Pol3), OWID.svg|thumb|upright=1.9|Share of one-year-olds vaccinated against polio in 2015<ref>{{cite web |title=Share of one-year-olds vaccinated against polio (Pol3) |url=https://ourworldindata.org/grapher/polio-vaccine-coverage-of-one-year-olds |website=Our World in Data |access-date=4 March 2020 |archive-date=22 February 2020 |archive-url=https://web.archive.org/web/20200222015955/https://ourworldindata.org/grapher/polio-vaccine-coverage-of-one-year-olds |url-status=live }}</ref>]]

In countries with endemic polio or where the risk of imported cases is high, the WHO recommends OPV vaccine at birth followed by a primary series of three OPV doses and at least one IPV dose starting at 6 weeks of age, with a minimum of 4 weeks between OPV doses. In countries with more than 90% immunization coverage and low risk of importation, the WHO recommends one or two IPV doses starting at two months of age followed by at least two OPV doses, with the doses separated by 4–8 weeks depending on the risk of exposure. In countries with the highest levels of coverage and the lowest risks of importation and transmission, the WHO recommends a primary series of three IPV injections, with a booster dose after an interval of six months or more if the first dose was administered before two months of age.<ref name="WHO2016" />

==Side effects==
The inactivated polio vaccines are very safe. Mild redness or pain may occur at the site of injection. They are generally safe to be given to [[pregnancy|pregnant]] women and those who have [[HIV/AIDS]], but are otherwise well.<ref name="WHO2016" />

=== Allergic reaction to the vaccine ===
Inactivated polio vaccine can cause an allergic reaction in a few people, since the vaccine contains trace amounts of [[Antibiotic|antibiotics]], [[streptomycin]], [[polymyxin B]], and [[neomycin]]. It should not be given to anyone who has an allergic reaction to these medicines. Signs and symptoms of an allergic reaction, which usually appear within minutes or a few hours after receiving the injected vaccine, include breathing difficulties, weakness, hoarseness or wheezing, heart-rate fluctuations, skin rash, and dizziness.<ref>{{Cite web|title=Common and Rare Side Effects for poliovirus vaccine injection|url=https://www.webmd.com/drugs/2/drug-14411/poliovirus-vaccine-injection/details/list-sideeffects|access-date=24 August 2021|website=Webmd|archive-date=24 August 2021|archive-url=https://web.archive.org/web/20210824070346/https://www.webmd.com/drugs/2/drug-14411/poliovirus-vaccine-injection/details/list-sideeffects|url-status=live}}</ref>

=== Vaccine-associated paralytic polio ===
A potential adverse effect of the Sabin OPV is caused by its known potential to recombine to a form that causes neurological infection and paralysis.<ref name="Shimizu_2004">{{cite journal | vauthors = Shimizu H, Thorley B, Paladin FJ, Brussen KA, Stambos V, Yuen L, Utama A, Tano Y, Arita M, Yoshida H, Yoneyama T, Benegas A, Roesel S, Pallansch M, Kew O, Miyamura T | title = Circulation of type 1 vaccine-derived poliovirus in the Philippines in 2001 | journal = Journal of Virology | volume = 78 | issue = 24 | pages = 13512–13521 | date = December 2004 | pmid = 15564462 | pmc = 533948 | doi = 10.1128/JVI.78.24.13512-13521.2004 }}</ref> The Sabin OPV results in vaccine-associated paralytic poliomyelitis (VAPP) in around one individual per every 2.7{{nbsp}}million doses administered, with symptoms identical to wild polio.<ref name="GPEI-OPV" /> Due to its improved genetic stability, the novel OPV (nOPV) has a reduced risk of this occurring.<ref>{{Cite web |date=April 2023 |title=nOPV2: Clinical Development and Evidence Summary |url=https://polioeradication.org/wp-content/uploads/2023/05/EN_nOPV2-Clinical-Development-Summary_Apr-2023.pdf |access-date=10 August 2024 |website=Global Polio Eradication Initiative}}</ref>

===Contamination concerns===
{{further|Vaccine contamination with SV40}}
In 1960, the [[rhesus monkey]] kidney cells used to prepare the poliovirus vaccines were determined to be infected with the [[SV40|simian virus-40]] (SV40),<ref name=SV>{{cite web| title = Simian Virus 40 (SV40), Polio Vaccine, and Cancer | publisher = U.S. [[Centers for Disease Control and Prevention]] (CDC) | date = 22 April 2004 | url = https://www.cdc.gov/vaccinesafety/updates/archive/polio_and_cancer_factsheet.htm | archive-url = https://web.archive.org/web/20130522091608/http://www.cdc.gov/vaccinesafety/updates/archive/polio_and_cancer_factsheet.htm | archive-date = 22 May 2013 | access-date = 22 May 2013}}</ref> which was also discovered in 1960 and is a naturally occurring virus that infects monkeys. In 1961, SV40 was found to cause tumors in [[rodent]]s.<ref name="Eddy_1961">{{cite journal|vauthors=Eddy BE, Borman GS, Berkeley WH, Young RD|date=May 1961|title=Tumors induced in hamsters by injection of rhesus monkey kidney cell extracts|journal=Proceedings of the Society for Experimental Biology and Medicine|volume=107|pages=191–197|doi=10.3181/00379727-107-26576|pmid=13725644|s2cid=31275908}}</ref> More recently, the virus was found in certain forms of [[cancer]] in humans, for instance [[brain tumor|brain]] and [[bone tumor]]s, [[pleural]] and [[peritoneal]] mesothelioma, and some types of [[non-Hodgkin lymphoma]].<ref>{{cite journal|vauthors=Carbone M|date=December 1999|title=Simian virus 40 and human tumors: It is time to study mechanisms|journal=Journal of Cellular Biochemistry|volume=76|issue=2|pages=189–193|doi=10.1002/(SICI)1097-4644(20000201)76:2<189::AID-JCB3>3.0.CO;2-J|pmid=10618636|s2cid=795975 }}</ref><ref>{{cite journal|vauthors=Vilchez RA, Kozinetz CA, Arrington AS, Madden CR, Butel JS|date=June 2003|title=Simian virus 40 in human cancers|journal=The American Journal of Medicine|volume=114|issue=8|pages=675–684|doi=10.1016/S0002-9343(03)00087-1|pmid=12798456}}</ref> However, SV40 has not been determined to cause these cancers.<ref name=Engels>{{cite journal | vauthors = Engels EA | s2cid = 5861910 | title = Cancer risk associated with receipt of vaccines contaminated with simian virus 40: epidemiologic research | journal = Expert Review of Vaccines | volume = 4 | issue = 2 | pages = 197–206 | date = April 2005 | pmid = 15889993 | doi = 10.1586/14760584.4.2.197 | url = https://zenodo.org/record/1235758 | access-date = 30 June 2019 | archive-date = 20 April 2020 | archive-url = https://web.archive.org/web/20200420144252/https://zenodo.org/record/1235758 | url-status = live }}</ref>

SV40 was found to be present in stocks of the injected form of the IPV in use between 1955 and 1963;<ref name=SV/> it is not found in the OPV form.<ref name=SV/> Over 98 million Americans received one or more doses of polio vaccine between 1955 and 1963, when a proportion of vaccine was contaminated with SV40; an estimated 10–30 million Americans may have received a dose of vaccine contaminated with SV40.<ref name=SV/> Later analysis suggested that vaccines produced by the former [[Soviet bloc]] countries until 1980, and used in the [[USSR]], [[China]], [[Japan]], and several [[Africa]]n countries, may have been contaminated, meaning hundreds of millions more may have been exposed to SV40.<ref>{{cite magazine | vauthors = Bookchin D| title = Vaccine scandal revives cancer fear | magazine = New Scientist | date = 7 July 2004 |url=https://www.newscientist.com/news/news.jsp?id=ns99996116| archive-url = https://web.archive.org/web/20040720074452/http://www.newscientist.com/news/news.jsp?id=ns99996116| archive-date=20 July 2004 | access-date = 29 November 2008 }}</ref>

In 1998, the [[National Cancer Institute]] undertook a large study, using cancer case information from the institute's SEER database. The published findings from the study revealed no increased incidence of cancer in persons who may have received vaccine containing SV40.<ref name="Strickler_1998">{{cite journal|vauthors=Strickler HD, Rosenberg PS, Devesa SS, Hertel J, Fraumeni JF, Goedert JJ|date=January 1998|title=Contamination of poliovirus vaccines with simian virus 40 (1955–1963) and subsequent cancer rates|journal=JAMA|volume=279|issue=4|pages=292–295|doi=10.1001/jama.279.4.292|pmid=9450713|doi-access=free}}</ref> Another large study in Sweden examined cancer rates of 700,000 individuals who had received potentially contaminated polio vaccine as late as 1957; the study again revealed no increased cancer incidence between persons who received polio vaccines containing SV40 and those who did not.<ref name="Olin_1998">{{cite journal|vauthors=Olin P, Giesecke J|year=1998|title=Potential exposure to SV40 in polio vaccines used in Sweden during 1957: no impact on cancer incidence rates 1960 to 1993|journal=Developments in Biological Standardization|volume=94|pages=227–233|pmid=9776244}}</ref> The question of whether SV40 causes cancer in humans remains controversial, however, and the development of improved assays for detection of SV40 in human tissues will be needed to resolve the controversy.<ref name=Engels/>
[[File:Bundesarchiv B 145 Bild-F025952-0015, Bonn, Gesundheitsamt, Schutzimpfung.jpg|thumb|Doses of oral polio vaccine are added to [[sugar cube]]s for use in a 1967 vaccination campaign in [[Bonn]], [[West Germany]]]]
During the race to develop an oral polio vaccine, several large-scale human trials were undertaken. By 1958, the National Institutes of Health had determined that OPV produced using the Sabin strains was the safest.<ref name=Sanofi/> Between 1957 and 1960, however, [[Hilary Koprowski]] continued to administer his vaccine around the world. In Africa, the vaccines were administered to roughly one million people in the Belgian territories (now the [[Democratic Republic of the Congo]], [[Rwanda]], and [[Burundi]]).<ref name="Plotkin">{{cite journal|vauthors=Plotkin SA|date=April 2001|title=CHAT oral polio vaccine was not the source of human immunodeficiency virus type 1 group M for humans|journal=Clinical Infectious Diseases|volume=32|issue=7|pages=1068–1084|doi=10.1086/319612|pmid=11264036|doi-access=free}}</ref><ref name=Kowproski5>{{cite journal | vauthors = Koprowski H | title = Historical aspects of the development of live virus vaccine in poliomyelitis | journal = British Medical Journal | volume = 2 | issue = 5192 | pages = 85–91 | date = July 1960 | pmid = 14410975 | pmc = 2096806 | doi = 10.1136/bmj.2.5192.85 }}</ref> The results of these human trials have been controversial,<ref name=Collins_2000>{{cite news | vauthors = Collins H | title = The Gulp Heard Round the World | page = D-1 | website = The Philadelphia Inquirer | date = 6 November 2000 | url = http://www.koprowski.net/Polio+Article.htm | access-date = 29 November 2008 |url-status = usurped| archive-url = https://web.archive.org/web/20040405233046/http://www.koprowski.net/Polio%20Article.htm | archive-date = 5 April 2004 | df = dmy-all }}</ref> and unfounded [[OPV AIDS hypothesis|accusations in the 1990s]] arose that the vaccine had created the conditions necessary for transmission of [[simian immunodeficiency virus]] from [[Common chimpanzee|chimpanzee]]s to humans, causing [[HIV/AIDS]]. These hypotheses, however, [[OPV AIDS hypothesis|have been conclusively refuted]].<ref name="Plotkin" /> By 2004, cases of poliomyelitis in Africa had been reduced to just a small number of isolated regions in the western portion of the continent, with sporadic cases elsewhere. Recent local opposition to vaccination campaigns has evolved due to lack of adequate information,<ref>{{cite news |url=https://news.bbc.co.uk/2/hi/africa/2070634.stm |publisher=BBC News Online |title=Nigeria Muslims oppose polio vaccination |date=27 June 2002 |access-date=29 November 2008 |url-status = live|archive-url=https://web.archive.org/web/20081129152933/http://news.bbc.co.uk/2/hi/africa/2070634.stm |archive-date=29 November 2008 }}</ref><ref>{{cite news |vauthors=Dugger CW, McNeil DG |url=https://www.nytimes.com/2006/03/20/international/asia/20polio.html |title=Rumor, Fear and Fatigue Hinder Final Push to End Polio |work=[[The New York Times]] |date=20 March 2006 |access-date=29 November 2008 |url-status = live|archive-url=https://web.archive.org/web/20081210212451/http://www.nytimes.com/2006/03/20/international/asia/20polio.html?pagewanted=2 |archive-date=10 December 2008 }}</ref> often relating to fears that the vaccine might induce [[Infertility|sterility]].<ref>{{cite news |url=https://news.bbc.co.uk/2/hi/africa/4539757.stm |publisher=[[BBC News Online]] |title=Anti-polio vaccine Malians jailed |date=12 May 2005 |access-date=29 November 2008 |url-status = live|archive-url=https://web.archive.org/web/20060110000559/http://news.bbc.co.uk/2/hi/africa/4539757.stm |archive-date=10 January 2006 }}</ref> The disease has since resurged in [[Nigeria]] and several other African nations without necessary information, which [[epidemiologist]]s believe is due to refusals by certain local populations to allow their children to receive the polio vaccine.<ref name="Jegede"/>

==Manufacture==

===Inactivated===
The Salk vaccine, IPV, is based on three wild, [[virulent]] reference strains, Mahoney (type 1 poliovirus), MEF-1 (type 2 poliovirus), and Saukett (type 3 poliovirus), grown in a type of monkey [[kidney]] tissue culture ([[Vero cell]] line), which are then inactivated with [[formalin]].<ref name=Kew_2005/> The injected Salk vaccine confers [[Immunoglobulin G|IgG]]-mediated immunity in the bloodstream, which prevents polio infection from progressing to [[viremia]] and protects the [[motor neurons]], thus eliminating the risk of [[bulbar polio]] and [[post-polio syndrome]].

In the United States, the vaccine is administered along with the [[tetanus vaccine|tetanus]], [[diphtheria]], and [[acellular]] [[pertussis]] vaccines ([[DTaP]]) and a pediatric dose of [[hepatitis B]] vaccine.<ref name = PinkPages/> In the UK, IPV is combined with tetanus, diphtheria, pertussis, and ''[[Haemophilus influenzae]]'' type b vaccines.<ref name="UK">{{cite book|title=Immunisation Against Infectious Disease|vauthors=((Joint Committee on Vaccination and Immunisation))|publisher=Stationery Office|year=2006|isbn=978-0-11-322528-6|veditors=Salisbury D, Ramsay M, Noakes K|location=Edinburgh|pages=313–329|chapter=26: Poliomyelitis|chapter-url=http://www.immunisation.nhs.uk/files/GB_26_polio.pdf|archive-url=https://web.archive.org/web/20070615150746/http://www.immunisation.nhs.uk/files/GB_26_polio.pdf|archive-date=15 June 2007}}</ref>

===Attenuated===
[[File:Immunization Certificate.jpg|thumb|Sabin immunization certificate]]
[[File:Poliomyelitis Vaccine Type I Type III in Dragee Candy (Human Diploid Cell), Live at PRC70 Exhibition (20191203153024).jpg|thumb|Example of OPV in [[dragee]] candy]]
OPV is an [[attenuated vaccine]], produced by the passage of the virus through nonhuman cells at a sub[[physiological]] temperature, which produces spontaneous mutations in the viral genome.<ref name="Sabin_1960">{{cite journal|vauthors=Sabin AB, Ramos-Alvarez M, Alvarez-Amezquita J, Pelon W, Michaels RH, Spigland I, Koch MA, Barnes JM, Rhim JS|date=August 1960|title=Live, orally given poliovirus vaccine. Effects of rapid mass immunization on population under conditions of massive enteric infection with other viruses|journal=JAMA|volume=173|issue=14|pages=1521–1526|doi=10.1001/jama.1960.03020320001001|pmid=14440553}}</ref> Oral polio vaccines were developed by several groups, one of which was led by [[Albert Sabin]]. Other groups, led by Hilary Koprowski and [[H. R. Cox|H.R. Cox]], developed their attenuated vaccine strains. In 1958, the NIH created a special committee on live polio vaccines. The various vaccines were carefully evaluated for their ability to induce immunity to polio while retaining a low incidence of neuropathogenicity in monkeys. Large-scale clinical trials performed in the Soviet Union in the late 1950s to early 1960s by [[Mikhail Chumakov]] and his colleagues demonstrated the safety and high efficacy of the vaccine.<ref>{{cite journal | vauthors = Sabin AB | s2cid = 45655185 | title = Role of my cooperation with Soviet scientists in the elimination of polio: possible lessons for relations between the U.S.A. and the USSR | journal = Perspectives in Biology and Medicine | volume = 31 | issue = 1 | pages = 57–64 | year = 1987 | pmid = 3696960 | doi = 10.1353/pbm.1987.0023 }}</ref><ref>{{cite journal|vauthors=Benison S|year=1982|title=International medical cooperation: Dr. Albert Sabin, live poliovirus vaccine and the Soviets|journal=Bulletin of the History of Medicine|volume=56|issue=4|pages=460–483|pmid=6760938}}</ref> Based on these results, the Sabin strains were chosen for worldwide distribution.<ref name = Sanofi>{{cite web | title = Competition to develop an oral vaccine | work = Conquering Polio | publisher = [[Sanofi Pasteur]] SA |date=2 February 2007 |url = http://www.polio.info/polio-eradication/front/templates/index.jsp?siteCode=POLIO&codeRubrique=34&lang=EN| archive-url = https://web.archive.org/web/20071007095443/http://www.polio.info/polio-eradication/front/templates/index.jsp?siteCode=POLIO&codeRubrique=34&lang=EN | archive-date=7 October 2007}}</ref> Fifty-seven [[nucleotide]] substitutions distinguish the attenuated Sabin 1 strain from its virulent parent (the Mahoney serotype), two nucleotide substitutions attenuate the Sabin 2 strain, and 10 substitutions are involved in attenuating the Sabin 3 strain.<ref name=Kew_2005/> The primary attenuating factor common to all three Sabin vaccines is a mutation located in the virus's [[internal ribosome entry site]],<ref>{{cite journal|vauthors=Ochs K, Zeller A, Saleh L, Bassili G, Song Y, Sonntag A, Niepmann M|date=January 2003|title=Impaired binding of standard initiation factors mediates poliovirus translation attenuation|journal=Journal of Virology|volume=77|issue=1|pages=115–122|doi=10.1128/JVI.77.1.115-122.2003|pmc=140626|pmid=12477816}}</ref> which alters [[stem-loop]] structures and reduces the ability of poliovirus to translate its RNA template within the host cell.<ref>{{cite journal|vauthors=Gromeier M, Bossert B, Arita M, Nomoto A, Wimmer E|date=February 1999|title=Dual stem loops within the poliovirus internal ribosomal entry site control neurovirulence|journal=Journal of Virology|volume=73|issue=2|pages=958–964|doi=10.1128/JVI.73.2.958-964.1999|pmc=103915|pmid=9882296}}</ref> The attenuated poliovirus in the Sabin vaccine replicates very efficiently in the gut, the primary site of infection and replication, but is unable to replicate efficiently within [[nervous system]] tissue. In 1961, type 1 and 2 [[monovalent vaccine|monovalent]] oral poliovirus vaccine (MOPV) was licensed, and in 1962, type 3 MOPV was licensed. In 1963, trivalent OPV (TOPV) was licensed, and became the vaccine of choice in the United States and most other countries of the world, largely replacing the inactivated polio vaccine.<ref name="Pearce">{{cite journal | vauthors = Pearce JM | title = Salk and Sabin: poliomyelitis immunisation | journal = Journal of Neurology, Neurosurgery, and Psychiatry | volume = 75 | issue = 11 | pages = 1552 | date = November 2004 | pmid = 15489385 | pmc = 1738787 | doi = 10.1136/jnnp.2003.028530 }}</ref> A second wave of mass immunizations led to a further dramatic decline in the number of polio cases. Between 1962 and 1965, about 100 million Americans (roughly 56% of the population at that time) received the Sabin vaccine. The result was a substantial reduction in the number of poliomyelitis cases, even from the much-reduced levels following the introduction of the Salk vaccine.<ref name=Smallman>{{cite book | vauthors = Smallman-Raynor M |title=Poliomyelitis: A World Geography: Emergence to Eradication |publisher=Oxford University Press (US) |year=2006 |isbn=978-0-19-924474-4|page= }}{{page needed|date=August 2021}}</ref>

OPV is usually provided in vials containing 10–20 doses of vaccine. A single dose of oral polio vaccine (usually two drops) contains 1,000,000 infectious units of Sabin 1 (effective against PV1), 100,000 infectious units of the Sabin 2 strain, and 600,000 infectious units of Sabin 3. The vaccine contains small traces of antibiotics—neomycin and streptomycin—but does not contain [[preservative]]s.<ref name=PAHO>{{cite book |title=Poliomyelitis Eradication: Field Guide |publisher=Pan American Health Organization |location=Washington |year=2006 |isbn=978-92-75-11607-4|page= }}{{page needed|date=August 2021}}</ref>

==History==
{{See also|Cold War tensions and the polio vaccine}}
In a generic sense, vaccination works by priming the [[immune system]] with an "[[immunogen]]". Stimulating immune response, by use of an infectious agent, is known as [[immunization]]. The development of immunity to polio efficiently blocks person-to-person transmission of wild poliovirus, thereby protecting both individual vaccine recipients and [[herd immunity|the wider community]].<ref name=Fine/>

The development of two polio vaccines led to the first modern mass [[inoculation]]s. The last cases of paralytic poliomyelitis caused by endemic transmission of wild virus in the United States occurred in 1979, with an outbreak among the [[Amish]] in several [[Midwest]] states.<ref name = PinkPages>{{cite book | veditors = Atkinson W, Hamborsky J, McIntyre L, Wolfe S| title = Epidemiology and Prevention of Vaccine-Preventable Diseases (The Pink Book) | edition = 10th | publisher = Public Health Foundation | location = Washington, D.C. | year = 2008 | url = https://www.cdc.gov/vaccines/pubs/pinkbook/downloads/polio-508.pdf | access-date = 29 November 2008 |archive-url=https://web.archive.org/web/20080924184516/http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/polio-508.pdf |archive-date=24 September 2008}}</ref>

=== 1930s ===

In the early 1930s, [[Maurice Brodie]] led a team from the public health laboratory of the city of New York, while [[John A. Kolmer]] collaborated with the [[Temple University College of Public Health|Research Institute of Cutaneous Medicine]] in Philadelphia.<ref name=":3">{{cite thesis|vauthors=Hovern D|title=The Trials and Triumphs of the American Polio Vaccine|year=2018|publisher=Cooper Medical School of Rowan University|url=https://rdw.rowan.edu/cmsru_capstones/4|access-date=19 July 2021|archive-date=21 July 2021|archive-url=https://web.archive.org/web/20210721042834/https://rdw.rowan.edu/cmsru_capstones/4/|url-status=live}}</ref><ref>{{Cite web|title=Vaccine Testing and Vulnerable Human Subjects |website=History of Vaccines|url=https://www.historyofvaccines.org/index.php/content/articles/vaccine-testing-and-vulnerable-human-subjects|access-date=18 July 2021|archive-date=2 August 2021|archive-url=https://web.archive.org/web/20210802132238/https://www.historyofvaccines.org/index.php/content/articles/vaccine-testing-and-vulnerable-human-subjects|url-status=dead}}</ref><ref name=":0">{{Cite journal| vauthors =Löwy I |date=1 April 2006|title=Book Review|journal=Medical History|volume=50|issue=2|pages=253–254|doi=10.1017/S0025727300009790|issn=0025-7273|pmc=1472109}}</ref>

==== Kolmer's live vaccine ====
Kolmer began his vaccine development project in 1932 and ultimately focused on producing an attenuated or ''live virus vaccine''. Inspired by the success of vaccines for rabies and yellow fever, he hoped to use a similar process to denature the polio virus.<ref name=":3" /> To go about [[Attenuated vaccine|attenuating]] his polio vaccine, he repeatedly passed the virus through monkeys.<ref name=":4">{{Cite book| vauthors = Gould T |title=A Summer Plague: Polio and Its Survivors|year=1997|publisher=Yale University Press|isbn=978-0300072761|location=New Haven|oclc=38243151}}</ref> Using methods of production that were later described as "hair-raisingly amateurish, the therapeutic equivalent of bath-tub gin",<ref>{{Cite book| vauthors = Wilson JR |title=Margin of Safety: The Story of Poliomyelitis Vaccine|publisher=Collins|year=1963|location=Garden City, New York|oclc=630735949}}</ref> Kolmer ground the spinal cords of his infected monkeys and soaked them in a salt solution. He then filtered the solution through mesh, treated it with [[Ricinoleic acid|ricinolate]], and refrigerated the product for 14 days<ref name=":3" /> to ultimately create what would later be prominently critiqued as a "veritable witches brew".<ref>Paul, J. R. (1971). ''A History of Poliomyelitis''. New Haven: Yale University Press.{{ISBN?}}{{page needed|date=August 2021}}</ref>

In keeping with the norms of the time, Kolmer completed a relatively small animal trial with 42 monkeys before proceeding to [[Self-experimentation in medicine|self-experimentation]] in 1934.<ref name=":2">{{Cite book| vauthors = Halpern SA |title=Lesser harms: The morality of risk in medical research|publisher=University of Chicago Press|year=2006|location=Chicago, Illinois|oclc=877210630}}</ref> He tested his vaccine upon himself, his two children, and his assistant.<ref name=":2" /> He gave his vaccine to just 23 more children before declaring it safe and sending it out to doctors and health departments for a larger test of efficacy.<ref name=":2" /> By April 1935, he was able to report having tested the vaccine on 100 children without ill effect.<ref name=":5">{{Cite journal| vauthors = Berk LB |date=1989|title=Polio Vaccine Trials of 1935|journal=Transactions & Studies of the College of Physicians of Philadelphia|volume=11|issue=4|pages=321–336|pmid=2692236}}</ref> Kolmer's first formal presentation of results did not come about until November 1935, when he presented the results of 446 children and adults he had vaccinated with his attenuated vaccine.<ref name=":5" /> He also reported that together the Research Institute of Cutaneous Medicine and the [[Marion Merrell Dow|Merrell Company of Cincinnati]] (the manufacturer who held the patent for his ricinoleating process) had distributed 12,000 doses of vaccine to some 700 physicians across the United States and Canada.<ref name=":5" /> Kolmer did not describe any monitoring of this experimental vaccination program, nor did he provide these physicians with instructions in how to administer the vaccine or how to report side effects.<ref name=":5" /> Kolmer dedicated the bulk of his publications thereafter to explaining what he believed to be the cause of the 10+ reported cases of paralytic polio following vaccination, in many cases in towns where no polio outbreak had occurred.<ref name=":5" /><ref name="Offit_2007" /> Six of these cases had been fatal.<ref name=":5" /> Kolmer had no control group, but asserted that many more children would have gotten sick.<ref name="Offit_2007" />

==== Brodie's inactivated vaccine ====
At nearly the same time as Kolmer's project, [[Maurice Brodie]] had joined immunologist [[William Hallock Park|William H. Park]] at the [[New York City Health Department]], where they worked together on poliovirus. With the aid of grant funding from the President's Birthday Ball Commission (a predecessor to what would become the [[March of Dimes]]), Brodie was able to pursue the development of an inactivated or "killed virus" vaccine. Brodie's process also began by grinding the spinal cords of infectious monkeys and then treating the cords with various germicides,<ref name=":6">{{Cite journal|vauthors=Broadie M, Park W|date=5 October 1935|title=Active immunization against poliomyelitis|url=http://ccat.sas.upenn.edu/goldenage/wonder/Archive/Science/wd_brodie%26park.htm|journal=Journal of the American Medical Association|volume=105|issue=14|pages=1089–1093|doi=10.1001/jama.1935.02760400005002|s2cid=1640997|access-date=19 July 2021|archive-date=19 July 2021|archive-url=https://web.archive.org/web/20210719142753/http://ccat.sas.upenn.edu/goldenage/wonder/Archive/Science/wd_brodie%26park.htm|url-status=live|url-access=subscription}}</ref> ultimately finding a solution of [[formaldehyde]] to be the most effective. By 1 June 1934, Brodie was able to publish his first scholarly article describing his successful induction of immunity in three monkeys with inactivated poliovirus.<ref>{{cite journal| vauthors = Brodie M |title=Active immunization in monkeys against poliomyelitis with germicidally inactivated virus|journal=The Journal of Immunology|volume=28|number=1|year=1935|pages=1–18|doi=10.4049/jimmunol.28.1.1 }}</ref><ref name=":7">{{Cite web|vauthors=Johnston K|date=22 February 2021|title=The tragic story of a Canadian vaccine trailblazer|url=https://www.macleans.ca/society/the-tragic-story-of-a-canadian-vaccine-trailblazer/|access-date=18 July 2021|website=[[Maclean's]]|archive-date=19 July 2021|archive-url=https://web.archive.org/web/20210719142802/https://www.macleans.ca/society/the-tragic-story-of-a-canadian-vaccine-trailblazer/|url-status=live}}</ref> Through continued study on an additional 26 monkeys, Brodie ultimately concluded that administration of live virus vaccine tended to result in [[humoral immunity]], while administration of killed virus vaccine tended to result in [[Cell-mediated immunity|tissue immunity]].<ref name=":5" />

Soon after, following a similar protocol to Kolmer's, Brodie proceeded with self-experimentation upon himself and his co-workers at the [[New York State Department of Health|NYC Health Department]] laboratory.<ref name=":2" /> Brodie's progress was eagerly covered by popular press, as the public hoped for a successful vaccine to become available.<ref name=":7" /> Such reporting did not make mention of the 12 children in a New York City Asylum who were subjected to early safety trials.<ref name=":2" /> As none of the subjects experienced ill effects, Park, described by contemporaries as "never one to let grass grow under his feet",<ref>{{cite book |vauthors=Oshinsky DM |title=Polio: An American Story |date=2005 |publisher=Oxford University Press |isbn=978-0-19-515294-4 |page=57 |url=https://books.google.com/books?id=p4YRDAAAQBAJ&pg=PA57 |access-date=23 March 2022 |archive-date=25 November 2023 |archive-url=https://web.archive.org/web/20231125140209/https://books.google.com/books?id=p4YRDAAAQBAJ&pg=PA57#v=onepage&q&f=false |url-status=live }}</ref> declared the vaccine safe.<ref name=":4" /> When a severe polio outbreak overwhelmed [[Kern County, California]], it became the first trial site for the new vaccine on very short notice. Between November 1934 and May 1935, over 1,500 doses of the vaccine were administered in Kern County. While initial results were very promising, insufficient staffing and poor protocol design left Brodie open to criticism when he published the California results in August 1935.<ref name=":7" /><ref name=":5" /> Through private physicians, Brodie also conducted a broader field study, including 9,000 children who received the vaccine and 4,500 age- and location-matched controls who did not receive a vaccine. Again, the results were promising. Of those who received the vaccine, only a few went on to develop polio. Most had been exposed before vaccination and none had received the full series of vaccine doses being studied.<ref name=":5" /> Additionally, a polio epidemic in [[Raleigh, North Carolina]], provided an opportunity for the [[United States Public Health Service|U.S. Public Health Service]] to conduct a highly structured trial of the Brodie vaccine using funding from the Birthday Ball Commission.<ref name=":4" /><ref name=":5" />

==== Academic reception ====
While their work was ongoing, the larger community of [[bacteriologist]]s began to raise concerns regarding the safety and efficacy of the new poliovirus vaccines.<ref name=":1">{{cite book| vauthors = Rivers T |year=1967|title=Tom Rivers: reflections on a life in medicine and science: an oral history memoir|publisher=MIT Press|hdl=2027/heb.05734|isbn=978-0262020268|url=https://hdl.handle.net/2027/heb.05734}}</ref> At this time, very little oversight of medical studies occurred and the ethical treatment of study participants largely relied upon moral pressure from [[Peer review|peer academic]] scientists.<ref name=":3" /> Brodie's inactivated vaccines faced scrutiny from many who felt killed virus vaccines could not be efficacious. While researchers were able to replicate the tissue immunity he had produced in his animal trials, the prevailing wisdom was that [[humoral immunity]] was essential for an efficacious vaccine.<ref name=":5" /> Kolmer directly questioned the killed virus approach in scholarly journals.<ref name=":6" /> Kolmer's studies, however, had raised even more concern with increasing reports of children becoming paralysed following vaccination with his live-virus vaccine and notably, with paralysis beginning at the arm rather than the foot in many cases.<ref name=":8">{{cite journal | vauthors = | title = Poliomyelitis | journal = American Journal of Public Health and the Nation's Health | volume = 26 | issue = 2 | pages = 181–183 | date = February 1936 | pmid = 18014373 | pmc = 1562619 | doi = 10.2105/AJPH.26.2.181 }}</ref> Both Kolmer and Brodie were called to present their research at the Annual Meeting of the [[American Public Health Association]] in [[Milwaukee]], Wisconsin, in October 1935.<ref name=":1" /> Additionally, [[Thomas Milton Rivers|Thomas M. Rivers]] was asked to discuss each of the presented papers as a prominent critic of the vaccine development effort.<ref name=":1" /> This resulted in the [[American Public Health Association|APHA]] arranging a symposium on poliomyelitis to be delivered at the annual meeting of their southern branch the following month.<ref name=":1" /> During the discussion at this meeting, James Leake of the U.S. Public Health Service stood to immediately present clinical evidence that the Kolmer vaccine had caused several deaths and then allegedly accused Kolmer of being a murderer.<ref name=":1" /> As Rivers recalled in his oral history, "All hell broke loose, and it seemed as if everybody was trying to talk at the same time&nbsp;... Jimmy Leake used the strongest language that I have ever heard used at a scientific meeting."<ref name=":1" /> In response to the attacks from all sides, Brodie was reported to have stood up and stated, "It looks as though, according to Dr. Rivers, my vaccine is no good, and according to Dr. Leake, Dr Kolmer's is dangerous."<ref name=":1" /> Kolmer simply responded by stating, "Gentlemen, this is one time I wish the floor would open up and swallow me."<ref name=":1" /> Ultimately, Kolmer's live vaccine was undoubtedly shown to be dangerous and had already been withdrawn in September 1935 before the Milwaukee meeting.<ref name=":8" /><ref name="Offit_2007" /><ref name=":5" /> While the consensus of the symposium was largely skeptical of the efficacy of Brodie's vaccine, its safety was not in question and the recommendation was for a much larger, well-controlled trial.<ref name=":8" /> However, when three children became ill with paralytic polio following a dose of the vaccine, the directors of the [[Warm Springs Historic District|Warm Springs Foundation]] in Georgia (acting as the primary funders for the project) requested it be withdrawn in December 1935.<ref name=":8" /> Following its withdrawal, the previously observed moratorium on human poliomyelitis vaccine development resumed and another attempt would not be made for nearly 20 years.<ref name=":5" /><ref name="Offit_2007" />

While Brodie had arguably made the most progress in the pursuit of a poliovirus vaccine, he suffered the most significant career repercussions due to his status as a less widely known researcher.<ref name=":7" /> Modern researchers recognize that Brodie may well have developed an effective polio vaccine, but the basic science and technology of the time were insufficient to understand and use this breakthrough.<ref name=":5" /> Brodie's work using formalin-inactivated virus later became the basis for the Salk vaccine, but he did not live to see this success.<ref name=":5" /> Brodie was fired from his position within three months of the symposium's publication.<ref name=":5" /> While he was able to find another laboratory position, he died of a heart attack only three years later at age 36.<ref name=":5" /><ref name=":7" /> By contrast, Park, who was believed in the community to be reaching senility at this point in his older age, was able to retire from his position with honors<ref name=":1" /> before he died in 1939.<ref name=":4" /> Kolmer, already an established and well-respected researcher, returned to [[Temple University]] as a professor of medicine.<ref name=":5" /> Kolmer had a very productive career, receiving multiple awards, and publishing countless papers, articles, and textbooks until his retirement in 1957.<ref name=":4" /><ref name=":1" /><ref name="Offit_2007" /><ref>{{Cite web|url=http://www.aai.org/About/History/Past-Presidents-and-Officers/JohnAKolmer|title=John A. Kolmer, M.D.|publisher=American Association of Immunologists|access-date=28 November 2017|archive-date=1 December 2017|archive-url=https://web.archive.org/web/20171201033155/http://www.aai.org/About/History/Past-Presidents-and-Officers/JohnAKolmer|url-status=live}}</ref>

===1948===
A breakthrough came in 1948 when a research group headed by [[John Enders]] at the [[Children's Hospital Boston]] successfully cultivated the poliovirus in human tissue in the laboratory.<ref name="Enders">{{cite journal | vauthors = Enders JF, Weller TH, Robbins FC | title = Cultivation of the Lansing Strain of Poliomyelitis Virus in Cultures of Various Human Embryonic Tissues | journal = Science | volume = 109 | issue = 2822 | pages = 85–87 | date = January 1949 | pmid = 17794160 | doi = 10.1126/science.109.2822.85 | bibcode = 1949Sci...109...85E }}</ref> This group had recently successfully grown [[mumps]] in [[cell culture]]. In March 1948, [[Thomas H. Weller]] was attempting to grow ''varicella'' virus in embryonic lung tissue. He had inoculated the planned number of tubes when he noticed that a few unused tubes. He retrieved a sample of [[mouse brain]] infected with poliovirus and added it to the remaining test tubes, on the off chance that the virus might grow. The ''varicella'' cultures failed to grow, but the polio cultures were successful. This development greatly facilitated vaccine research and ultimately allowed for the development of vaccines against polio. Enders and his colleagues, [[Thomas H. Weller]] and [[Frederick C. Robbins]], were recognized in 1954 for their efforts with a [[Nobel Prize in Physiology or Medicine]].<ref name="Nobel_1954">{{cite web | title=The Nobel Prize in Physiology or Medicine 1954 | publisher=The Nobel Foundation | url=http://nobelprize.org/nobel_prizes/medicine/laureates/1954/ | access-date=29 November 2008 |url-status = live| archive-url=https://web.archive.org/web/20081219224515/http://nobelprize.org/nobel_prizes/medicine/laureates/1954/ | archive-date=19 December 2008 | df=dmy-all }}</ref> Other important advances that led to the development of polio vaccines included the identification of three poliovirus serotypes (poliovirus type 1 – PV1, or Mahoney; PV2, Lansing; and PV3, Leon), the finding that before paralysis, the virus must be present in the blood, and the demonstration that administration of antibodies in the form of [[gamma globulin]] protects against paralytic polio.<ref name=":1" /><ref name="Kew_2005">{{cite journal | vauthors = Kew OM, Sutter RW, de Gourville EM, Dowdle WR, Pallansch MA | title = Vaccine-derived polioviruses and the endgame strategy for global polio eradication | journal = Annual Review of Microbiology | volume = 59 | pages = 587–635 | date = 2005 | pmid = 16153180 | doi = 10.1146/annurev.micro.58.030603.123625 | url = https://zenodo.org/record/1235033 | access-date = 30 June 2019 | archive-date = 9 July 2020 | archive-url = https://web.archive.org/web/20200709053801/https://zenodo.org/record/1235033 | url-status = live }}</ref><ref name="pmid13034471">{{cite journal|vauthors=Hammon WM, Coriell LL, Wehrle PF, Stokes J|date=April 1953|title=Evaluation of Red Cross gamma globulin as a prophylactic agent for poliomyelitis. IV. Final report of results based on clinical diagnoses|journal=Journal of the American Medical Association|volume=151|issue=15|pages=1272–1285|pmid=13034471}}</ref>

=== 1950–1955 ===
{{See also| Announcement of Polio vaccine success}}
[[File:Salk headlines.jpg|thumb|left|1955 newspaper headlines on the development of an effective polio vaccine]]
During the early 1950s, polio rates in the U.S. were above 25,000 annually; in 1952 and 1953, the U.S. experienced an outbreak of 58,000 and 35,000 polio cases, respectively, up from a typical number of some 20,000 a year, with deaths in those years numbering 3,200 and 1,400.<ref>{{cite journal | url = https://ourworldindata.org/polio | vauthors = Ochmann S, Roser M | date = 9 November 2017 | title = Polio – Polio Cases (OWID based on US Public Health Service (1910–1951) and US Center for Disease Control (1960–2010)) | journal = Our World in Data | access-date = 26 March 2018 | archive-date = 28 March 2018 | archive-url = https://web.archive.org/web/20180328105153/https://ourworldindata.org/polio | url-status = live }}</ref> Amid this U.S. polio epidemic, millions of dollars were invested in finding and marketing a polio vaccine by commercial interests, including Lederle Laboratories in New York under the direction of [[H. R. Cox]]. Also working at Lederle was Polish-born [[virologist]] and [[immunologist]] [[Hilary Koprowski]] of the Wistar Institute in Philadelphia, who tested the first successful polio vaccine, in 1950.<ref name="Kowproski_obit"/><ref name=Kowproski5 /> His vaccine, however, being a live attenuated virus taken orally, was still in the research stage and would not be ready for use until five years after Jonas Salk's polio vaccine (a dead-virus injectable vaccine) had reached the market. Koprowski's attenuated vaccine was prepared by successive passages through the brains of Swiss albino mice. By the seventh passage, the vaccine strains could no longer infect nervous tissue or cause paralysis. After one to three further passages on rats, the vaccine was deemed safe for human use.<ref name="Sanofi" /><ref>{{cite journal|date=October 1947|title=Public Health Weekly Reports for October 10, 1947|journal=Public Health Reports|volume=62|issue=41|pages=1467–1498|pmc=1995293|pmid=19316151}}</ref> On 27 February 1950, Koprowski's live, attenuated vaccine was tested for the first time on an 8-year-old boy living at [[Letchworth Village]], an institution for physically and mentally disabled people located in New York. After the child had no side effects, Koprowski enlarged his experiment to include 19 other children.<ref name="Sanofi" /><ref>{{cite web |url=http://www.historyofvaccines.org/content/timelines/polio |title=Vaccine Timeline: Before Jenner and After COVID-19 |website=History of Vaccines | vauthors = Koprowski H |date=15 October 2010 |access-date=15 October 2010 |publisher=[[College of Physicians of Philadelphia]] |url-status = live|archive-url=http://arquivo.pt/wayback/20160515175017/http://www.historyofvaccines.org/content/timelines/polio |archive-date=15 May 2016 }}</ref>{{failed verification|reason=Does not mention Letchworth or Koprowski|date=April 2025}}

==== Jonas Salk ====
[[File:PittPolioVaccineCoL.jpg|thumb|right|Administration of the polio inoculation, including by [[Jonas Salk|Salk]] himself, in 1957 at the [[University of Pittsburgh]], where his team had developed the vaccine]]
[[File:Polio immunization days PHIL 2445.png|thumb|right|Mass polio vaccination in [[Columbus, Georgia]] circa 1961 for the National Polio Immunization Program]]

The first effective polio vaccine was developed in 1952 by [[Jonas Salk]] and a team at the [[University of Pittsburgh]] that included [[Julius Youngner]], Byron Bennett, L. James Lewis, and Lorraine Friedman, which required years of subsequent testing. Salk went on CBS radio to report a successful test on a small group of adults and children on 26 March 1953; two days later, the results were published in ''[[JAMA (journal)|JAMA]]''.<ref name = "Offit_2007">{{cite book| vauthors = Offit PA |title=The Cutter Incident: How America's First Polio Vaccine Led to the Growing Vaccine Crisis|publisher=Yale University Press|year=2007|page=38|isbn=978-0-300-12605-1}}</ref> [[Leone N. Farrell]] invented a key laboratory technique that enabled the mass production of the vaccine by a team she led in Toronto.<ref>{{Cite web|website=science.ca |title=Leone N. Farrell|url=http://www.science.ca/scientists/scientistprofile.php?pID=438|access-date=1 August 2021|archive-date=28 June 2020|archive-url=https://web.archive.org/web/20200628213420/http://www.science.ca/scientists/scientistprofile.php?pID=438|url-status=live}}</ref><ref>{{cite web |vauthors=Elliott CK |title=Leone Norwood Farrell, PhD |url=http://www.polioplace.org/people/leone-norwood-farrell-phd |website=polioplace |publisher=Post-polio Health International |access-date=10 August 2019 |date=March 2011 |archive-date=9 August 2019 |archive-url=https://web.archive.org/web/20190809151030/http://www.polioplace.org/people/leone-norwood-farrell-phd |url-status=live }}</ref> Beginning 23 February 1954, the vaccine was tested at [[Arsenal Middle School|Arsenal Elementary School]] and the [[D. T. Watson Home for Crippled Children|Watson Home for Children]] in [[Pittsburgh, Pennsylvania]].<ref name="Shors2008">{{cite book| vauthors = Shors T |title=Understanding viruses |url= https://books.google.com/books?id=VQeamKFwyvgC&pg=PA294 |access-date=22 February 2011|date=2008|publisher=Jones & Bartlett Learning|isbn=978-0-7637-2932-5|pages=294–|url-status = live|archive-url=https://web.archive.org/web/20140721060240/http://books.google.com/books?id=VQeamKFwyvgC&pg=PA294|archive-date=21 July 2014}}</ref>

Salk's vaccine was then used in a test called the Francis Field Trial, led by [[Thomas Francis, Jr.|Thomas Francis]], the largest medical experiment in history at that time. The test began with about 4,000 children at Franklin Sherman Elementary School in [[McLean, Virginia]],<ref name="Conis">{{cite journal|vauthors=Conis E|title=Political Ills|journal=Distillations|date=2016|volume=2|issue=2|pages=34–37|url=https://www.sciencehistory.org/distillations/magazine/political-ills|access-date=27 March 2018|archive-date=20 March 2018|archive-url=https://web.archive.org/web/20180320230802/https://www.sciencehistory.org/distillations/magazine/political-ills|url-status=live}}</ref><ref name="test">{{cite web | url = http://www.americanheritage.com/content/miracle-workers | vauthors = Oshinsky D | title = Miracle Workers | work = American Heritage | date =Winter 2010 | access-date = 1 September 2014 | archive-date = 3 September 2014 | archive-url = https://web.archive.org/web/20140903073856/http://www.americanheritage.com/content/miracle-workers | url-status = live }}</ref> and eventually involved 1.8 million children, in 44 states from [[Maine]] to [[California]].<ref name=MoD_2004>{{cite web | title = Polio Victory Remembered as March of Dimes Marks 50th Anniversary of Salk Vaccine Field Trials | work = News Desk | url = http://www.marchofdimes.org/news/polio-victory-remembered-as-march-of-dimes-marks-50th-anniversary-of-salk-vaccine-field-trials.aspx | date = 26 April 2004 | access-date = 14 November 2014 |url-status = live| archive-url = https://web.archive.org/web/20150927112220/http://www.marchofdimes.org/news/polio-victory-remembered-as-march-of-dimes-marks-50th-anniversary-of-salk-vaccine-field-trials.aspx | archive-date = 27 September 2015 | df = dmy-all }}</ref> By the conclusion of the study, roughly 440,000 received one or more injections of the vaccine, about 210,000 children received a [[placebo]], consisting of harmless [[culture media]], and 1.2 million children received no vaccination and served as a control group, who would then be observed to see if any contracted polio.<ref name = Sanofi/>

The results of the field trial were announced on 12 April 1955 (the tenth anniversary of the death of President [[Franklin D. Roosevelt]], whose [[Franklin D. Roosevelt's paralytic illness|paralytic illness]] was generally believed to have been caused by polio). The Salk vaccine had been 60–70% effective against PV1 (poliovirus type 1), over 90% effective against PV2 and PV3, and 94% effective against the development of bulbar polio.<ref name="Smith_1990">{{cite book | vauthors = Smith JS | title = Patenting the Sun: Polio and the Salk Vaccine | publisher = William Morrow & Co | year = 1990 | isbn = 978-0-688-09494-2 | url-access = registration | url = https://archive.org/details/patentingsunpoli00smit }}</ref> Soon after Salk's vaccine was licensed in 1955, children's vaccination campaigns were launched. In the U.S., following a mass immunization campaign promoted by the [[March of Dimes]], the annual number of polio cases fell from 35,000 in 1953 to 5,600 by 1957.<ref name="Sass">{{cite book |vauthors=Sorem A, Sass EJ, Gottfried G |title=Polio's legacy: an oral history |publisher=University Press of America |location=Washington, D.C. |year=1996 |isbn=978-0-7618-0144-3}}</ref> By 1961 only 161 cases were recorded in the United States.<ref name="Hinman">{{cite journal|vauthors=Hinman AR|date=June 1984|title=Landmark perspective: Mass vaccination against polio|journal=JAMA|volume=251|issue=22|pages=2994–2996|doi=10.1001/jama.1984.03340460072029|pmid=6371280}}</ref>

A week before the announcement of the Francis Field Trial results in April 1955, [[Pierre Lépine]] at the [[Pasteur Institute]] in Paris had also announced an effective polio vaccine.<ref>The Pasteur Institute stated that an anti-poliomyelitis vaccine, developed by Professor Pierre Lepine, would soon be produced in large quantities. (''The Times'', London, 4 April 1955.)</ref>{{fcn<!--If the statement in this ref tag is supposed to be a quotation, put it in quotation marks and ensure it's accurate-->|date=April 2025}}<ref>{{cite web| work = Archives de l'Institut Pasteur |title=Pierre Lépine (1901–1989) – Notice biographique|url=http://webext.pasteur.fr/archives/e_lep0.html |access-date=28 November 2016|url-status = live|archive-url=https://web.archive.org/web/20161128194930/http://webext.pasteur.fr/archives/e_lep0.html|archive-date=28 November 2016}}</ref>

====Safety incidents====
In April 1955, soon after mass polio vaccination began in the US, the Surgeon General began to receive reports of patients who contracted paralytic polio about a week after being vaccinated with the Salk polio vaccine from the [[Cutter Laboratories|Cutter]] pharmaceutical company, with the paralysis starting in the limb the vaccine was injected into.<ref name="Jonas Salk: A Life">{{Cite book| vauthors = Jacobs CD |title=Jonas Salk: A Life|publisher=Oxford University Press|year=2015|location=New York City|oclc=919967059}}</ref> The Cutter vaccine had been used in vaccinating 409,000 children in the western and midwestern United States.<ref>{{cite journal|date=August 1955|title=Technical Report on Poliomyelitis Vaccine|journal=Public Health Reports|volume=70|issue=8|pages=742}}</ref>
Later investigations showed that the Cutter vaccine had caused 260 cases of polio, killing 11.<ref name="Jonas Salk: A Life"/> In response, the Surgeon General pulled all polio vaccines made by Cutter Laboratories from the market, but not before 260 cases of paralytic illness had occurred. Eli Lilly, Parke-Davis, Pitman-Moore, and Wyeth polio vaccines were also reported to have paralyzed numerous children. It was soon discovered that some lots of Salk polio vaccine made by Cutter, Wyeth, and the other labs had not been properly inactivated, allowing live poliovirus into more than 100,000 doses of vaccine. In May 1955, the National Institutes of Health and Public Health Services established a Technical Committee on Poliomyelitis Vaccine to test and review all polio vaccine lots and advise the Public Health Service as to which lots should be released for public use. These incidents reduced public confidence in the polio vaccine, leading to a drop in vaccination rates.<ref name="Juskewitch2010">{{Cite journal |vauthors=Juskewitch JE, Tapia CJ, Windebank AJ |date=August 2010 |title=Lessons from the Salk polio vaccine: methods for and risks of rapid translation |journal=Clinical and Translational Science |type=Review |volume=3 |issue=4 |pages=182–185 |doi=10.1111/j.1752-8062.2010.00205.x |pmc=2928990 |pmid=20718820 |doi-access=free}}</ref>

===1961===
[[File:Gallo, Robert C. and Sabin, Albert B.jpg|thumb|upright|left|[[Albert Sabin]] (right) with [[Robert Gallo]], circa 1985]]
At the same time that Salk was testing his vaccine, both [[Albert Sabin]] and Hilary Koprowski continued working on developing a vaccine using live virus. During a meeting in Stockholm to discuss polio vaccines in November 1955, Sabin presented results obtained on a group of 80 volunteers, while Koprowski read a paper detailing the findings of a trial enrolling 150 people.<ref name=Sanofi/> Sabin and Koprowski both eventually succeeded in developing vaccines. Because of the commitment to the Salk vaccine in America, Sabin and Koprowski both did their testing outside the United States, Sabin in Mexico<ref name = "Sabin_1960" /> and the Soviet Union,<ref name=NMAH>{{cite web | url = http://amhistory.si.edu/polio/virusvaccine/vacraces2.htm | title = Two Vaccines: Sabin and Salk | work = Smithsonian National Museum of American History | date = 27 September 2021 | access-date = 24 April 2017 | archive-date = 20 January 2017 | archive-url = https://web.archive.org/web/20170120113212/http://amhistory.si.edu/polio/virusvaccine/vacraces2.htm | url-status = live }}</ref> Koprowski in the Congo and Poland.<ref name=Kowproski5/> In 1957, Sabin developed a trivalent vaccine containing attenuated strains of all three types of poliovirus.<ref name=NMAH /> In 1959, ten million children in the [[Soviet Union]] received the Sabin oral vaccine. For this work, Sabin was given the medal of the [[Order of Friendship of Peoples]], described as the Soviet Union's highest civilian honor.<ref>{{cite web | work = UPI | url = http://www.upi.com/Archives/1986/11/20/Sabin-receives-highest-Soviet-civilian-honor/6402532846800/ | title = Sabin receives highest Soviet civilian honor | date = 20 November 1986 | access-date = 25 April 2017 | archive-date = 25 April 2017 | archive-url = https://web.archive.org/web/20170425122629/http://www.upi.com/Archives/1986/11/20/Sabin-receives-highest-Soviet-civilian-honor/6402532846800/ | url-status = live }}</ref> Sabin's oral vaccine using live virus came into commercial use in 1961.<ref name=WHO2016/>

Once Sabin's oral vaccine became widely available, it supplanted Salk's injected vaccine, which had been tarnished in the public's opinion by the [[Cutter incident]] of 1955, in which Salk vaccines improperly prepared by one company resulted in several children dying or becoming paralyzed.<ref name = "Offit_2007" />

====Japan====
In the early 1960s, Japan Broadcasting Corporation (NHK) journalist Tetsu Ueda and his colleagues played a pivotal role in raising public awareness about polio outbreaks in Japan. NHK began broadcasting daily reports from regional bureaus on new polio cases, which significantly heightened public concern. This surge in national anxiety prompted the Minister of Health and Welfare to make a political decision to urgently import the Soviet live attenuated vaccine (Sabin), leading to rapid containment of the disease. According to Professor Munehiro Hirayama of the University of Tokyo, the success of this campaign was largely due to the passionate efforts of Ueda and the NHK team committed to polio eradication.<ref>{{citeweb|url=https://www.jspid.jp/wp-content/uploads/pdf/01902/019020189.pdf|title=Emergency Introduction of Live Polio Vaccine in Japan|author=Munehiro Hirayama|publisher=Journal of Pediatric Infectious and Immunology Vol.19 No.2|accessdate=2024-10-20}}</ref>
<ref name="konzetu">{{citeweb|url=https://jappan.zouri.jp/konzetu/e-mokuji.htm|title=Konzetu (Eradication) Movement Archives|author=Satoshi Ueda|accessdate=2025-10-02}}</ref>

=== 1987 ===
An enhanced-[[potency (pharmacology)|potency]] IPV was licensed in the United States in November 1987, and is currently the vaccine of choice there.<ref name = PinkPages/> The first dose of the polio vaccine is given shortly after birth, usually between 1 and 2 months of age, and a second dose is given at 4 months of age.<ref name=PinkPages/> The timing of the third dose depends on the vaccine formulation but should be given between 6 and 18 months of age.<ref name=UK/> A booster vaccination is given at 4 to 6 years of age, for a total of four doses at or before school entry.<ref name="Peds">{{cite journal|date=February 1997|title=Poliomyelitis prevention: recommendations for use of inactivated poliovirus vaccine and live oral poliovirus vaccine. American Academy of Pediatrics Committee on Infectious Diseases|journal=Pediatrics|volume=99|issue=2|pages=300–305|doi=10.1542/peds.99.2.300|pmid=9024465|doi-access=free}}</ref> In some countries, a fifth vaccination is given during [[adolescence]].<ref name=UK/> Routine vaccination of adults (18 years of age and older) in developed countries is neither necessary nor recommended because most adults are already immune and have a very small risk of exposure to wild poliovirus in their home countries.<ref name=PinkPages/> In 2002, a [[pentavalent]] (five-component) combination vaccine (called Pediarix)<ref>Full name: Diphtheria and Tetanus Toxoids and Acellular Pertussis Adsorbed, Hepatitis B (Recombinant) and Inactivated Poliovirus Vaccine Combined</ref><ref name=pediarix>{{cite web |title=Pediarix |url=https://www.fda.gov/vaccines-blood-biologics/vaccines/pediarix |website=U.S. [[Food and Drug Administration]] (FDA) |date=6 November 2019 |access-date=8 July 2020 |archive-date=22 September 2019 |archive-url=https://web.archive.org/web/20190922202657/https://www.fda.gov/vaccines-blood-biologics/vaccines/pediarix |url-status=live }}</ref> containing IPV was approved for use in the United States.<ref>{{cite web |url=https://www.fda.gov/media/75250/download |format=PDF |title=FDA Statistical Review and Evaluation |website=U.S. [[Food and Drug Administration]] (FDA) |access-date=8 July 2020 |archive-date=6 August 2020 |archive-url=https://web.archive.org/web/20200806060853/https://www.fda.gov/media/75250/download |url-status=dead }}</ref><ref name=pediarix/>

===1988===
[[File:Somali boy receives a polio vaccination.jpg|thumb|right|A [[Somali people|Somali]] boy is injected with inactivated poliovirus vaccine ([[Mogadishu]], 1993)]]

A global effort to eradicate polio, led by the [[World Health Organization]] (WHO), [[UNICEF]],<ref>{{cite news| vauthors = Mansoor H |title=Can India's social mobilisation strategy work in Pakistan?|url=http://tribune.com.pk/story/978251/can-indias-social-mobilisation-strategy-work-in-pakistan/|access-date=24 October 2015|newspaper=The Express Tribune|date=23 October 2015|url-status = live|archive-url=https://web.archive.org/web/20151024053606/http://tribune.com.pk/story/978251/can-indias-social-mobilisation-strategy-work-in-pakistan/|archive-date=24 October 2015}}</ref> and the [[The Rotary Foundation|Rotary Foundation]], began in 1988, and has relied largely on the oral polio vaccine developed by [[Albert Sabin]] and [[Mikhail Chumakov]] (Sabin-Chumakov vaccine).<ref name=Watch>{{cite web | vauthors = Mastny L | title = Eradicating Polio: A Model for International Cooperation | publisher = Worldwatch Institute | date = 25 January 1999 | url = http://www.worldwatch.org/node/1644 | access-date = 29 November 2008 |url-status = live| archive-url = https://web.archive.org/web/20061203222228/https://www.worldwatch.org/node/1644 | archive-date = 3 December 2006 | df = dmy-all }}</ref>

===After 1990===
Polio was eliminated in the Americas by 1994.<ref name="MMWR_1994">{{cite journal | title = Certification of poliomyelitis eradication – the Americas, 1994 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 43 | issue = 39 | pages = 720–722 | date = October 1994 | pmid = 7522302 | url = https://www.cdc.gov/mmwr/PDF/wk/mm4339.pdf | url-status = live | archive-url = https://web.archive.org/web/20170521163051/https://www.cdc.gov/mmwr/preview/mmwrhtml/00032760.htm | archive-date = 21 May 2017 }}</ref> The disease was officially eliminated in 36 Western Pacific countries, including China and Australia, in 2000.<ref name="Pacific">{{cite journal|year=2001|title=General News. Major Milestone reached in Global Polio Eradication: Western Pacific Region is certified Polio-Free|journal=Health Educ Res|volume=16|issue=1|pages=109–114|bibcode=2001PDiff..16..110Y|doi=10.1093/her/16.1.109| vauthors = Yamazaki S, Toraya H }}</ref><ref name="D'Souza_2002">{{cite journal | vauthors = D' Souza RM, Kennett M, Watson C | title = Australia declared polio-free | journal = Communicable Diseases Intelligence Quarterly Report | volume = 26 | issue = 2 | pages = 253–260 | date = 2002 | pmid = 12206379 }}</ref> Europe was declared polio-free in 2002.<ref name=WHO_Europe_2002>{{cite press release | title = Europe achieves historic milestone as Region is declared polio-free | publisher = [[World Health Organization]] (WHO) | date = 21 June 2002 | url =https://www.who.int/mediacentre/news/releases/releaseeuro02/en/index.html | access-date = 23 August 2008 |url-status = dead| archive-url = https://web.archive.org/web/20080916065107/http://www.who.int/mediacentre/news/releases/releaseeuro02/en/index.html | archive-date = 16 September 2008 | df = dmy-all }}</ref> Since January 2011, no cases of the disease have been reported in India, hence in February 2012, the country was taken off the WHO list of polio-endemic countries. In March 2014, India was declared a polio-free country.<ref>{{cite news| vauthors = Ray K |title=India wins battle against dreaded polio|newspaper=Deccan Herald|date=26 February 2012}}</ref><ref>{{cite news |title=India polio-free for a year: 'First time in history we're able to put up such a map' |url= http://www.telegraphindia.com/1120226/jsp/frontpage/story_15181357.jsp |access-date=26 February 2012 |newspaper=The Telegraph |date=26 February 2012 |url-status = dead|archive-url=https://web.archive.org/web/20120227220101/http://www.telegraphindia.com/1120226/jsp/frontpage/story_15181357.jsp|archive-date=27 February 2012 }}</ref><ref>{{Cite web|url=http://www.searo.who.int/entity/immunization/topics/polio/en/|title=India three years polio-free|website=[[World Health Organization]] (WHO)|access-date=19 February 2017|url-status = dead|archive-url=https://web.archive.org/web/20170301051406/http://www.searo.who.int/entity/immunization/topics/polio/en/|archive-date=1 March 2017}}</ref>

Although poliovirus transmission has been interrupted in much of the world, transmission of wild poliovirus does continue and creates an ongoing risk for the importation of wild poliovirus into previously polio-free regions. If importations of poliovirus occur, outbreaks of poliomyelitis may develop, especially in areas with low vaccination coverage and poor sanitation. As a result, high levels of vaccination coverage must be maintained.<ref name=MMWR_1994/> In November 2013, the WHO announced a polio outbreak in Syria. In response, the Armenian government put out a notice asking [[Syrian Armenians]] under age 15 to get the polio vaccine.<ref>{{cite web | vauthors = Barron L | url = http://cistranfinance.com/news/armenian-health-ministry-urges-syrian-armenian-children-to-get-polio-vaccine/666/ | title = Armenian Health Ministry: Syrian Armenian children need polio vaccine | archive-url = https://web.archive.org/web/20131219024041/http://cistranfinance.com/news/armenian-health-ministry-urges-syrian-armenian-children-to-get-polio-vaccine/666/ | archive-date=19 December 2013 | work = CISTran Finance | date = 4 November 2013 | access-date = 18 December 2013 }}</ref> As of 2014, polio virus had spread to 10 countries, mainly in Africa, Asia, and the [[Middle East]], with Pakistan, Syria, and [[Cameroon]] advising vaccinations to outbound travellers.<ref name="DarrasJr.2014">{{cite book| vauthors = De Vivo DC, Ryan MM, Jones HR, Darras BT |title=Neuromuscular Disorders of Infancy, Childhood, and Adolescence: A Clinician's Approach|url=https://books.google.com/books?id=JlECBAAAQBAJ&pg=PA161|year=2014|publisher=Elsevier Science|isbn=978-0-12-417127-5|page=161|url-status = live|archive-url=https://web.archive.org/web/20170423222313/https://books.google.com/books?id=JlECBAAAQBAJ&pg=PA161|archive-date=23 April 2017}}</ref>

Polio vaccination programs have been resisted by some people in Pakistan and Afghanistan – the two countries with remaining wild polio cases as of 2020.<ref>{{Cite web |title=Global polio eradication initiative applauds WHO African region for wild polio-free certification |url=https://www.who.int/news/item/25-08-2020-global-polio-eradication-initiative-applauds-who-african-region-for-wild-polio-free-certification |access-date=2025-07-19 |website=[[World Health Organization]] (WHO) }}</ref> Almost all Muslim religious and political leaders have endorsed the vaccine,<ref>{{cite book|title=The Missing Martyrs|first=Charles |last=Kurzman|publisher=[[Oxford University Press]]|page=130|quote=Resistance to polio vaccination is a fringe position. Almost every Muslim scholar and political leader has endorsed the vaccine, and all but a few Muslim-majority countries have wiped out the disease entirely.}}</ref> but a fringe minority believes that the vaccines are secretly being used for the sterilisation of Muslims.<ref name="Jegede">{{cite journal | vauthors = Jegede AS | title = What led to the Nigerian boycott of the polio vaccination campaign? | journal = PLOS Medicine | volume = 4 | issue = 3 | pages = e73 | date = March 2007 | pmid = 17388657 | pmc = 1831725 | doi = 10.1371/journal.pmed.0040073 | doi-access = free }}</ref> The fact that the [[CIA transnational health and economic activities#Using public aid for information|CIA organized a fake vaccination program in 2011]] to help find [[Osama bin Laden]] is an additional cause of distrust.<ref name="Pakistan">{{cite news|date=11 September 2016|title=Pakistan polio official killed in Peshawar: police|work=The Daily Star |location=Lebanon|url=https://www.dailystar.com.lb/News/World/2016/Sep-11/371570-pakistan-polio-official-killed-in-peshawar-police.ashx|url-status=live|access-date=11 September 2016|archive-url=https://web.archive.org/web/20160911122228/http://www.dailystar.com.lb/News/World/2016/Sep-11/371570-pakistan-polio-official-killed-in-peshawar-police.ashx|archive-date=11 September 2016}}</ref> In 2015, the WHO announced a deal with the [[Taliban]] to encourage them to distribute the vaccine in areas they control.<ref>{{cite news|url=https://www.bloomberg.com/news/articles/2015-12-15/taliban-join-global-effort-to-kill-off-polio-in-2016|title=Taliban Join Global Effort to Kill Off Polio in 2016| vauthors = Najafizada E |date=15 December 2015|work=Bloomberg|url-status = live|archive-url=https://web.archive.org/web/20170228052344/https://www.bloomberg.com/news/articles/2015-12-15/taliban-join-global-effort-to-kill-off-polio-in-2016|archive-date=28 February 2017}}</ref> However, the Pakistani Taliban was not supportive. On 11 September 2016, two unidentified gunmen associated with the Pakistani Taliban, Jamaat-ul-Ahrar, shot Zakaullah Khan, a doctor who was administering polio vaccines in Pakistan. The leader of the Jamaat-ul-Ahrar claimed responsibility for the shooting and stated that the group would continue this type of attack. Such resistance to and skepticism of vaccinations has consequently slowed down the polio eradication process within the two remaining endemic countries.<ref name="Pakistan" />

== Travel requirements ==
{{See also|Vaccination requirements for international travel}}
[[File:Polio vaccination travel requirements map.svg|thumb|Polio vaccination is required for travellers:
{{Legend|#000080|From all countries, to all countries}}
{{Legend|#0000FF|From some countries, to all countries}}
{{Legend|#800080|From some countries, to all countries}}
{{Legend|#008000|From some countries, to some countries}}
{{Legend|#87DE87|To some countries}}
{{Legend|#FFCC00|From some countries}}]]
Travellers who wish to enter or leave certain countries must be vaccinated against polio, usually at most 12 months and at least 4 weeks before crossing the border, and be able to present a vaccination record/certificate at the border checks.<ref name="WHO Travel and Health">{{Cite web |url=https://www.who.int/ith/CHAPTER_6_For_Publication.pdf |title=International Travel and Health. Chapter 6 – Vaccine-preventable diseases and vaccines (2019 update) |publisher=World Health Organization |date=2020 |access-date=2 December 2020 |archive-date=11 April 2020 |archive-url=https://web.archive.org/web/20200411151558/https://www.who.int/ith/CHAPTER_6_For_Publication.pdf |url-status=live }}</ref>{{rp|25–27}} Most requirements apply only to travel to or from so-called 'polio-endemic', 'polio-affected', 'polio-exporting', 'polio-transmission', or 'high-risk' countries.<ref name="WHO country list">{{Cite web |url=https://www.who.int/publications/m/item/countries-with-risk-of-yellow-fever-transmission-and-countries-requiring-yellow-fever-vaccination-(july-2019) |title=Countries with risk of yellow fever transmission and countries requiring yellow fever vaccination (July 2019) |publisher=World Health Organization |date=4 July 2019 |access-date=2 December 2020 |archive-date=27 January 2021 |archive-url=https://web.archive.org/web/20210127232029/https://www.who.int/publications/m/item/countries-with-risk-of-yellow-fever-transmission-and-countries-requiring-yellow-fever-vaccination-(july-2019) |url-status=live }}</ref> As of August 2020, Afghanistan and Pakistan are the only polio-endemic countries in the world (where [[polio eradication|wild polio has not yet been eradicated]]).<ref name=":9">{{Cite news| vauthors = Scherbel-Ball N |date=25 August 2020|title=Africa declared free of polio|work=BBC News|url=https://www.bbc.com/news/world-africa-53887947|access-date=25 August 2020|archive-date=26 August 2020|archive-url=https://web.archive.org/web/20200826154956/https://www.bbc.com/news/world-africa-53887947|url-status=live}}</ref> Several countries have additional precautionary polio vaccination travel requirements, for example to and from 'key at-risk countries', which as of December 2020 include China, Indonesia, Mozambique, Myanmar, and Papua New Guinea.<ref name="WHO country list"/><ref>{{Cite news |url=http://polioeradication.org/where-we-work/key-at-risk-countries/ |title=Key At-Risk Countries |work=Global Polio Eradication Initiative |publisher=World Health Organization |access-date=2 December 2020 |archive-date=29 April 2021 |archive-url=https://web.archive.org/web/20210429061349/https://polioeradication.org/where-we-work/key-at-risk-countries/ |url-status=live }}</ref>

{| class="wikitable sortable" style="text-align:left;" align="left" width=1100
|+ Polio vaccination requirements for international travel<ref name="WHO country list"/>
|-
! align="left" width=100 | Country
! Details
|-
| {{flag|Afghanistan}}
| Travellers from polio-endemic countries (Pakistan) need [[Carte Jaune]] proof of polio vaccination (received between 4 weeks and 12 months before departure) upon arrival. Residents and all travellers staying in Afghanistan longer than 4 weeks need proof of polio vaccination (received between 4 weeks and 12 months before departure) when departing from Afghanistan.<ref name="WHO country list"/><ref>{{Cite web |url=https://www.iamat.org/country/afghanistan/risk/polio |title=Afghanistan Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=1 October 2020 |access-date=2 December 2020 |archive-date=21 October 2020 |archive-url=https://web.archive.org/web/20201021023033/https://www.iamat.org/country/afghanistan/risk/polio |url-status=live }}</ref>
|-
| {{flag|Belize}}
| Travellers from Afghanistan and Pakistan need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival. Belize residents travelling to countries with confirmed polio cases also need proof of vaccination.<ref>{{Cite web |url=https://www.iamat.org/country/belize/risk/polio |title=Belize Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030223600/https://www.iamat.org/country/belize/risk/polio |url-status=live }}</ref>
|-
| {{flag|Brunei}}
| Travellers from polio-exporting countries need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/brunei-darussalam/risk/polio |title=Brunei Darussalam Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=1 December 2020 |archive-url=https://web.archive.org/web/20201201114654/https://www.iamat.org/country/brunei-darussalam/risk/polio |url-status=live }}</ref>
|-
| {{flag|Egypt}}
| Travellers from Afghanistan, Angola, Benin, Cameroon, the Central African Republic, China, Congo-Kinshasa, Ethiopia, Ghana, Indonesia, Kenya, Mozambique, Myanmar, Niger, Nigeria, Pakistan, Papua New Guinea, Philippines, and Somalia need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/egypt/risk/polio |title=Egypt Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308061617/https://www.iamat.org/country/egypt/risk/polio |url-status=live }}</ref>
|-
| {{flag|Georgia}}
| Travellers from at-risk countries need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival. Travellers without proof are offered OPV vaccination upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/georgia/risk/polio |title=Georgia Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=17 January 2021 |archive-url=https://web.archive.org/web/20210117032629/https://www.iamat.org/country/georgia/risk/polio |url-status=live }}</ref>
|-
| {{flag|India}}
| Travellers from Afghanistan, Congo-Kinshasa, Ethiopia, Kenya, Nigeria, Pakistan, Somalia, and Syria need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/india/risk/polio |title=India Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030230943/https://www.iamat.org/country/india/risk/polio |url-status=live }}</ref>
|-
| {{flag|Iran}}
| Travellers from Afghanistan, Pakistan, and Nigeria need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival. Travellers without proof will be vaccinated upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/iran/risk/polio |title=Iran Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030075425/https://www.iamat.org/country/iran/risk/polio |url-status=live }}</ref>
|-
| {{flag|Iraq}}
| Travellers aged 15+ from Afghanistan and Pakistan need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival; children under age 15 must have received three doses of polio vaccine before travel. Travellers without proof will be vaccinated upon arrival. Travellers departing from Iraq to Afghanistan and Pakistan must also provide proof of vaccination upon departure.<ref>{{Cite web |url=https://www.iamat.org/country/iraq/risk/polio |title=Iraq Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=20 January 2021 |archive-url=https://web.archive.org/web/20210120224455/https://www.iamat.org/country/iraq/risk/polio |url-status=live }}</ref>
|-
| {{flag|Jordan}}
| Travellers from Afghanistan and Pakistan need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/jordan/risk/polio |title=Jordan Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030073452/https://www.iamat.org/country/jordan/risk/polio |url-status=live }}</ref>
|-
| {{flag|Lebanon}}
| Travellers from and to polio-affected countries need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/lebanon/risk/polio |title=Lebanon Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030213817/https://www.iamat.org/country/lebanon/risk/polio |url-status=live }}</ref>
|-
| {{flag|Libya}}
| Travellers from Afghanistan and Pakistan need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/libya/risk/polio |title=Libya Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030221107/https://www.iamat.org/country/libya/risk/polio |url-status=live }}</ref>
|-
| {{flag|Maldives}}
| Travellers from and to polio-exporting countries, as well as [[Hajj]] and [[Umrah]] pilgrims, need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/maldives/risk/polio |title=Maldives Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030083714/https://www.iamat.org/country/maldives/risk/polio |url-status=live }}</ref>
|-
| {{flag|Morocco}}
| Travellers from polio-affected countries need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/morocco/risk/polio |title=Morocco Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=21 October 2020 |archive-url=https://web.archive.org/web/20201021023413/https://www.iamat.org/country/morocco/risk/polio |url-status=live }}</ref>
|-
| {{flag|Nepal}}
| Travellers from Afghanistan, Kenya, Nigeria, Pakistan, and Papua New Guinea need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/nepal/risk/polio |title=Nepal Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=21 September 2020 |archive-url=https://web.archive.org/web/20200921102600/https://www.iamat.org/country/nepal/risk/polio |url-status=live }}</ref>
|-
| {{flag|Oman}}
| Travellers from polio-exporting countries need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/oman/risk/polio |title=Oman Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=15 August 2020 |archive-url=https://web.archive.org/web/20200815075731/https://www.iamat.org/country/oman/risk/polio |url-status=live }}</ref>
|-
| {{flag|Pakistan}}
| Travellers from ALL countries planning to stay in Pakistan for more than 4 weeks need [[Carte Jaune]] proof of OPV vaccination upon arrival. Residents and all travellers staying in Pakistan longer than 4 weeks need proof of OPV vaccination when departing from Pakistan.<ref name="WHO country list"/><ref>{{Cite web |url=https://www.iamat.org/country/pakistan/risk/polio |title=Pakistan Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=21 October 2020 |archive-url=https://web.archive.org/web/20201021022622/https://www.iamat.org/country/pakistan/risk/polio |url-status=live }}</ref>
|-
| {{flag|Philippines}}
| Travellers from or to high-risk countries need [[Carte Jaune]] proof of polio vaccination upon arrival or before departure, respectively.<ref name="WHO country list"/> Due to an [[2019–20 Philippines polio outbreak|ongoing local VDPV2 outbreak]], the government recommends all others travellers to consider getting a polio vaccine or booster dose, depending on their situation.<ref>{{Cite web |url=https://www.iamat.org/country/philippines/risk/polio |title=Philippines Recommended Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=25 October 2020 |archive-url=https://web.archive.org/web/20201025045827/https://www.iamat.org/country/philippines/risk/polio |url-status=live }}</ref>
|-
| {{flag|Qatar}}
| Travellers from polio-exporting countries (identified by Qatar as: Afghanistan, Nigeria, Pakistan, and the Philippines) need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/qatar/risk/polio |title=Qatar Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=2 December 2020 |archive-url=https://web.archive.org/web/20201202030843/https://www.iamat.org/country/qatar/risk/polio |url-status=live }}</ref>
|-
| {{flag|Saint Kitts and Nevis}}
| Travellers from polio-endemic countries as identified by WHO (Afghanistan and Pakistan) need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref name="WHO country list"/><ref>{{Cite web |url=https://www.iamat.org/country/saint-kitts-and-nevis/risk/polio |title=Saint Kitts & Nevis Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=4 December 2020 |archive-url=https://web.archive.org/web/20201204075910/https://www.iamat.org/country/saint-kitts-and-nevis/risk/polio |url-status=live }}</ref>
|-
| {{flag|Saudi Arabia}}
| Travellers from active-transmission (including wild or vaccine-derived poliovirus) and at-risk countries, as well as all travellers from Afghanistan, Congo-Kinshasa, Mozambique, Myanmar, Niger, Nigeria, Pakistan, Papua New Guinea, Somalia, Syria, and Yemen, need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival. Regardless of immunisation status, all travellers from Afghanistan, Myanmar, Nigeria, Pakistan, Papua New Guinea, Somalia, Syria, and Yemen will be given an Oral Polio Vaccine dose upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/saudi-arabia/risk/polio |title=Saudi Arabia Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=27 February 2021 |archive-url=https://web.archive.org/web/20210227182449/https://www.iamat.org/country/saudi-arabia/risk/polio |url-status=live }}</ref>
|-
| {{flag|Seychelles}}
| Travellers from countries with polio outbreaks need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival.<ref>{{Cite web |url=https://www.iamat.org/country/seychelles/risk/polio |title=Seychelles Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=4 August 2020 |archive-url=https://web.archive.org/web/20200804144538/https://www.iamat.org/country/seychelles/risk/polio |url-status=live }}</ref>
|-
| {{flag|Syria}}
| Travellers from Cameroon, Equatorial Guinea, and Pakistan need [[Carte Jaune]] proof of OPV or IPV vaccination (received between 4 weeks and 12 months before departure) upon arrival. All Syria residents departing Syria to any country also need proof of vaccination.<ref>{{Cite web |url=https://www.iamat.org/country/syria/risk/polio |title=Syria Required Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030073925/https://www.iamat.org/country/syria/risk/polio |url-status=live }}</ref>
|-
| {{flag|Ukraine}}
| Long-term visitors departing to states with wild or circulating vaccine-derived poliovirus transmission should present [[Carte Jaune]] proof of vaccination with at least one dose of bivalent OPV or IPV (received between 4 weeks and 12 months before departure). Persons obliged to undertake urgent international travel must be immunised with a single dose of polio vaccine before their departure.<ref name="WHO country list"/> There is also risk of poliovirus transmission inside Ukraine itself, and travellers to Ukraine are recommended to be up to date with their polio vaccination before entry.<ref>{{Cite web |url=https://www.iamat.org/country/ukraine/risk/polio |title=Ukraine Recommended Vaccinations: Polio |publisher=International Association for Medical Assistance to Travellers (IAMAT) |date=23 October 2020 |access-date=2 December 2020 |archive-date=24 January 2021 |archive-url=https://web.archive.org/web/20210124000735/https://www.iamat.org/country/ukraine/risk/polio |url-status=live }}</ref>
|}
{{Clear}}

==Society and culture==

===Cost===
{{As of|2015}}, the [[Global Alliance for Vaccines and Immunization]] supplies the inactivated vaccine to developing countries for as little as {{Currency|0.75|EURO}} (about {{USD|{{To USD|0.75|EUR}}}}) per dose in 10-dose vials.<ref>{{cite web | title = Availability and price of inactivated polio vaccine | publisher = The Global Polio Eradication Initiative | url = http://www.polioeradication.org/Mediaroom/Newsstories(old)/Newsstories2013/tabid/488/iid/354/Default.aspx#sthash.jGhJ4YUB.dpuf | archive-url = https://web.archive.org/web/20150411021753/http://www.polioeradication.org/Mediaroom/Newsstories(old)/Newsstories2013/tabid/488/iid/354/Default.aspx | archive-date = 11 April 2015 |url-status = dead}}</ref>

===Misconceptions===

A misconception has been present in Pakistan that the polio vaccine contains ''[[haram]]'' ingredients and could cause impotence and infertility in male children, leading some parents not to have their children vaccinated. This belief is most common in the [[Khyber Pakhtunkhwa]] province and the [[FATA]] region. Attacks on polio vaccination teams have also occurred, thereby hampering international efforts to eradicate polio in Pakistan and globally.<ref>{{cite news|url=https://news.bbc.co.uk/2/hi/south_asia/6299325.stm|title=Impotence fears hit polio drive|work=BBC News Online|access-date=15 December 2015|url-status = live|archive-url=https://web.archive.org/web/20151009221811/http://news.bbc.co.uk/2/hi/south_asia/6299325.stm|archive-date=9 October 2015|date=25 January 2007}}</ref><ref>{{cite web|url=http://www.dawn.com/news/1156931|title=Lab tests show polio vaccine is not 'Haram'| vauthors = Junaidi I |work=dawn.com|access-date=15 December 2015|url-status = live|archive-url=https://web.archive.org/web/20151222173149/http://www.dawn.com/news/1156931|archive-date=22 December 2015|date=14 January 2015}}</ref>

== References ==
{{Reflist}}

== Further reading ==
{{refbegin}}
* {{cite book | title = Immunisation against infectious disease | chapter = Polio: the green book, chapter 26 | chapter-url = https://www.gov.uk/government/publications/polio-the-green-book-chapter-26 | publisher = Public Health England | veditors = Ramsay M | url = https://www.gov.uk/government/collections/immunisation-against-infectious-disease-the-green-book | year = 2013 | location = London | access-date = 23 December 2019 | archive-date = 12 November 2019 | archive-url = https://web.archive.org/web/20191112005859/https://www.gov.uk/government/publications/pneumococcal-the-green-book-chapter-25 | url-status = live }}
* {{cite book | publisher = U.S. [[Centers for Disease Control and Prevention]] (CDC) | title = Epidemiology and Prevention of Vaccine-Preventable Diseases | veditors = Hall E, Wodi AP, Hamborsky J, Morelli V, Schillie S | edition = 14th | location = Washington D.C. | year = 2021 | chapter = Chapter 18: Poliomyelitis | chapter-url = https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-18-poliomyelitis.html | url = https://www.cdc.gov/pinkbook/hcp/table-of-contents/ | access-date = 23 December 2019 | archive-date = 30 December 2016 | archive-url = https://web.archive.org/web/20161230001534/https://www.cdc.gov/vaccines/pubs/pinkbook/index.html | url-status = live }}
* {{cite book | vauthors = Routh JA, Oberste MS, Patel M | chapter = Chapter 12: Poliomyelitis | chapter-url = https://www.cdc.gov/surv-manual/php/table-of-contents/chapter-12-poliomyelitis.html | veditors = Roush SW, Baldy LM, Hall MH | title = Manual for the surveillance of vaccine-preventable diseases | publisher = U.S. [[Centers for Disease Control and Prevention]] (CDC) | location = Atlanta, Georgia | url = https://www.cdc.gov/surv-manual/php/index.html | year = 2018 | access-date = 23 December 2019 | archive-date = 1 August 2020 | archive-url = https://web.archive.org/web/20200801192220/https://www.cdc.gov/vaccines/pubs/surv-manual/ | url-status = live }}
{{refend}}

== External links ==
* {{cite web | title=Polio Vaccine Information Statement | website=U.S. [[Centers for Disease Control and Prevention]] (CDC) | url=https://www.cdc.gov/vaccines/hcp/current-vis/polio.html }}
* [https://www.pbs.org/wgbh/aso/databank/entries/dm52sa.html 'People and Discoveries: Salk Produces Polio Vaccine 1952'] [[Public Broadcasting Service]] (PBS)
* {{MeshName|Poliovirus Vaccines}}

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[[Category:Polio vaccines| ]]
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[[Category:1955 introductions]]
[[Category:American inventions]]
[[Category:Inactivated vaccines]]
[[Category:Live vaccines]]
[[Category:Vaccines]]
[[Category:World Health Organization essential medicines (vaccines)]]
[[Category:Wikipedia medicine articles ready to translate]]