විකිපීඩියා

"පෝලියෝ එන්නත" හි සංශෝධන අතර වෙනස්කම්

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සංස්කරණය-අළුත් පිටුවෙන් අන්තර්ගතය පැරණි පිටුවට
ඉංග්‍රීසි ලිපියේ ඉතිරි ටික එක් කිරීම
52 පේළිය:
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. 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]], who claims to have created the first successful polio vaccine, in 1950. 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 |title=Weekly Reports for OCTOBER 10, 1947 |journal=Public Health Rep |volume=62 |issue=41 |pages=1467–1498 |date=October 1947 |pmid=19316151 |pmc=1995293 |doi= }}</ref> On February 27, 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 the physically and mentally disabled located in New York. After the child suffered 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 = Interview with Hilary Koprowski, sourced at History of Vaccines website | first=Hilary |last=Koprowski | date=15 October 2010 | accessdate=15 October 2010| publisher=[[College of Physicians of Philadelphia]]}}</ref>
 
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 | author = Atkinson W, Hamborsky J, McIntyre L, Wolfe S, eds. | title = Epidemiology and Prevention of Vaccine-Preventable Diseases (The Pink Book) | edition = 10th ed. (2nd printing) | publisher = Public Health Foundation | location = Washington, D.C. | year = 2008 | url = http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/polio-508.pdf |format=PDF| accessdate = 2008-11-29}}{{dead link|date=January 2013}}</ref> A global effort to eradicate polio, led by the [[World Health Organization]], [[UNICEF]], and [[The Rotary Foundation]], began in 1988 and has relied largely on the oral polio vaccine developed by [[Albert Sabin]].<ref name= Watch>{{cite web| last = Mastny| first = Lisa | title = Eradicating Polio: A Model for International Cooperation |publisher = Worldwatch Institute | date = 1999-01-25 | url = http://www.worldwatch.org/node/1644 | accessdate = 2008-11-29}}</ref> The disease was entirely eradicated in the [[Americas]] by 1994.<ref name=MMWR_1994>{{cite journal | title = International Notes Certification of Poliomyelitis Eradication — the Americas, 1994 | journal = Morbidity and Mortality Weekly Report | publisher = Centers for Disease Control and Prevention | volume= 43 | issue= 39 | pages = 720–722 | year=1994 | url = http://www.cdc.gov/mmwr/preview/mmwrhtml/00032760.htm | pmid = 7522302| author1= Centers for Disease Control and Prevention (CDC) }}</ref> Polio was officially eradicated in 36 Western Pacific countries, including China and Australia in 2000.<ref name= Pacific>{{cite journal | author = ,| title = General News. Major Milestone reached in Global Polio Eradication: Western Pacific Region is certified Polio-Free | journal = Health Educ Res | year = 2001 | volume = 16 | issue = 1 | page = 109 | url= http://her.oxfordjournals.org/cgi/reprint/16/1/109.pdf | format = PDF| doi = 10.1093/her/16.1.109}}</ref><ref name="D'Souza_2002">{{cite journal |author=D'Souza R, Kennett M, Watson C |title=Australia declared polio free |journal=Commun Dis Intell |volume=26 |issue=2 |pages=253–60 |year=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 = European Region of the World Health Organization | date = 2002-06-21 | url = http://www.who.int/mediacentre/news/releases/releaseeuro02/en/index.html | accessdate = 2008-08-23 }}</ref> Since January 2011, there were no reported cases of the disease in India, and hence in February 2012, the country was taken off the WHO list of polio endemic countries. It is reported that if there are no cases of polio in the country for two more years, it will be declared as a polio-free country.<ref>{{cite news|last=Ray|first=Kalyan|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|accessdate=26 February 2012|newspaper=The Telegraph|date=26 February 2012}}</ref> As of 2008, polio remains [[Endemic (epidemiology)|endemic]] in only three countries: [[Nigeria]], [[Pakistan]], and [[Afghanistan]].<ref name="eradication">{{cite journal |title=Update on vaccine-derived polioviruses |journal=MMWR Morb. Mortal. Wkly. Rep. |volume=55 |issue=40 |pages=1093–7 |date=October 2006 |pmid=17035927 |url=http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5540a3.htm |author1= Centers for Disease Control and Prevention (CDC)}}</ref><ref>{{cite news|last=Rafael |first=PePedro |url=http://www.nytimes.com/video/2012/12/20/world/asia/100000001967352/polio-campaign-crisis-in-pakistan.html |title=Polio Campaign Crisis in Pakistan - Video - The New York Times |location=40.755978;-73.990396 |publisher=Nytimes.com |date=2012-12-20 |accessdate=2013-01-03}}</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 occurs, 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/>
 
== Inactivated vaccine ==
[[File:PittPolioVaccineCoL.jpg|thumb|right|Administration of the polio inoculation, including by [[Jonas Salk|Salk]] himself, in 1957 at the [[University of Pittsburgh]] where he and his team had developed the vaccine]]
The first effective polio vaccine was developed in 1952 by [[Jonas Salk]] at the [[University of Pittsburgh]], but it would require years of testing. To encourage patience, Salk went on CBS radio to report a successful test on a small group of adults and children on March 26, 1953; two days later the results were published in [[JAMA (journal)|JAMA]].<ref>{{cite book|last=Offit|first=Paul A.|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=0-300-12605-0}}</ref>
 
The Salk vaccine, or ''inactivated poliovirus 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 [[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]].
 
Beginning February 23, 1954, the vaccine was tested at Arsenal Elementary School and the [[D. T. Watson Home for Crippled Children|Watson Home for Children]] in [[Pittsburgh, Pennsylvania]].<ref name="Shors2008">{{cite book|author=Teri Shors|title=Understanding viruses|url=http://books.google.com/books?id=VQeamKFwyvgC&pg=PA294|accessdate=22 February 2011|date=14 March 2008|publisher=Jones & Bartlett Learning|isbn=978-0-7637-2932-5|pages=294–}}</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. The test began with some 4,000 children at Franklin Sherman Elementary School in [[McLean, Virginia]],<ref name="test">[http://www.americanheritage.com/articles/magazine/ah/2010/4/2010_4_85.shtml David Oshinsky]{{dead link|date=January 2013}} "Miracle Workers," ''American Heritage'', Winter 2010.</ref> and would eventually involve 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.com/aboutus/10651_11681.asp | date = 2004-04-26 | accessdate = 2008-11-29 | archiveurl = http://web.archive.org/web/20080919033102/http://www.marchofdimes.com/aboutus/10651_11681.asp <!--Added by H3llBot--> | archivedate = 2008-09-19}}</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 April 12, 1955 (the tenth anniversary of the death of President [[Franklin D. Roosevelt]], whose [[Franklin D. Roosevelt's paralytic illness|paralysis]] 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 |last = Smith | first = Jane S. | title = Patenting the Sun: Polio and the Salk Vaccine | publisher = William Morrow & Co |year= 1990 |isbn=0-688-09494-5}}</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 |author=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=0-7618-0144-8 |url=http://www.cloudnet.com/~edrbsass/poliotimeline.htm }}</ref> By 1961 only 161 cases were recorded in the United States.<ref name= Hinman>{{cite journal |author=Hinman A |title=Landmark perspective: Mass vaccination against polio |journal=JAMA |volume=251 |issue=22 |pages=2994–6 |year=1984 |pmid = 6371280 |doi=10.1001/jama.251.22.2994}}</ref>
 
[[File:Somali boy receives a polio vaccination.jpg|thumb|left|A [[Somali people|Somali]] boy is injected with inactivated poliovirus vaccine ([[Mogadishu]], 1993)]]
An enhanced-[[potency (pharmacology)|potency]] IPV was licensed in the United States in November 1987, and is currently the vaccine of choice in the United States.<ref name = PinkPages/> The first dose of polio vaccine is given shortly after birth, usually between 1–2 months of age, 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 6–18 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 |title=Poliomyelitis prevention: recommendations for use of inactivated poliovirus vaccine and live oral poliovirus vaccine. American Academy of Pediatrics Committee on Infectious Diseases|url=http://pediatrics.aappublications.org/cgi/content/full/99/2/300 |journal=Pediatrics |volume=99 |issue=2 |pages=300–5 |year=1997 |pmid=9024465|doi=10.1542/peds.99.2.300}}</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]] (5-component) combination vaccine (called Pediarix) containing IPV was approved for use in the United States. The vaccine also contains combined [[diphtheria]], [[tetanus]], 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 |author=Joint Committee on Vaccination and Immunisation, David Salisbury (Editor), Mary Ramsay (Editor), Karen Noakes (Editor) |title=Immunisation Against Infectious Disease |chapter= 26: Poliomyelitis | url=http://www.immunisation.nhs.uk/files/GB_26_polio.pdf |format=PDF|publisher=Stationery Office |location=Edinburgh |year= 2006 |pages=313–29 |isbn=0-11-322528-8 }}{{dead link|date=January 2013}}</ref> When the current formulation of IPV is used, 90% or more of individuals develop protective antibody to all three [[serotype]]s of poliovirus after two doses of inactivated polio vaccine (IPV), and at least 99% are immune to poliovirus following three doses. The duration of immunity induced by IPV is not known with certainty, although a complete series is thought to provide protection for many years.<ref name=Robertson_1993>{{cite web | last = Robertson | first = Susan | title = Module 6: Poliomyelitis | work = The Immunological Basis for Immunization Series | publisher = [[World Health Organization]] (Geneva, Switzerland) | url = http://www.who.int/vaccines-documents/DocsPDF-IBI-e/mod6_e.pdf |format=PDF| accessdate = 2008-11-29}}</ref>
 
== Oral vaccine ==
[[File:Polio vaccine poster.jpg|thumb|This 1963 poster featured CDC’s national symbol of [[public health]], the "Wellbee", encouraging the public to receive an oral polio vaccine.]]
 
Oral polio vaccine (OPV) is a live-[[attenuated vaccine]], produced by the passage of the virus through non-human cells at a sub-[[physiological]] temperature, which produces spontaneous mutations in the viral genome.<ref>{{cite journal |author=Sabin A |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 |pages=1521–6 |year= 1960 |pmid = 14440553 |author-separator=, |author2=Ramos-Alvarez M |author3=Alvarez-Amezquita J |display-authors=3 |last4=Pelon |first4=W |last5=Michaels |first5=RH |last6=Spigland |first6=I |last7=Koch |first7=MA |last8=Barnes |first8=JM |last9=Rhim |first9=JS |doi=10.1001/jama.1960.03020320001001 |issue=14}}</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 own attenuated vaccine strains. In 1958, the [[National Institutes of Health]] 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 late 1950s — early 1960s by [[Mikhail Chumakov]] and his colleagues demonstrated safety and high efficacy of the vaccine.<ref>{{cite journal |author=Sabin AB |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=Perspect. Biol. Med. |volume=31 |issue=1 |pages=57–64 |year=1987 |pmid=3696960 }}</ref><ref>{{cite journal |author=Benison S |title=International medical cooperation: Dr. Albert Sabin, live poliovirus vaccine and the Soviets |journal=Bull Hist Med |volume=56 |issue=4 |pages=460–83 |year=1982 |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=2007-02-02 |url = http://www.polio.info/polio-eradication/front/templates/index.jsp?siteCode=POLIO&codeRubrique=34&lang=EN| archiveurl = http://web.archive.org/web/20071007095443/http://www.polio.info/polio-eradication/front/templates/index.jsp?siteCode=POLIO&codeRubrique=34&lang=EN | archivedate = 2007-10-16 }}</ref>
 
There are 57 [[nucleotide]] substitutions which 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]] (IRES)<ref>{{cite journal |author=Ochs K |title=Impaired Binding of Standard Initiation Factors Mediates Poliovirus Translation Attenuation |journal=J. Virol. |volume=77 |issue=1 |pages=115–22 |date=January 2003 |pmid=12477816 |pmc=140626 |doi= 10.1128/JVI.77.1.115-122.2003|url=http://jvi.asm.org/cgi/pmidlookup?view=long&pmid=12477816 |author-separator=, |author2=Zeller A |author3=Saleh L |display-authors=3 |last4=Bassili |first4=G. |last5=Song |first5=Y. |last6=Sonntag |first6=A. |last7=Niepmann |first7=M.}}</ref> which alters [[stem-loop]] structures, and reduces the ability of poliovirus to translate its RNA template within the host cell.<ref>{{cite journal |author=Gromeier M, Bossert B, Arita M, Nomoto A, Wimmer E |title=Dual Stem Loops within the Poliovirus Internal Ribosomal Entry Site Control Neurovirulence |journal=J. Virol. |volume=73 |issue=2 |pages=958–64 |date=February 1999 |pmid=9882296 |pmc=103915 |url=http://jvi.asm.org/cgi/pmidlookup?view=long&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. OPV also proved to be superior in administration, eliminating the need for sterile syringes and making the vaccine more suitable for mass vaccination campaigns. OPV also provided longer lasting [[immunity (medical)|immunity]] than the Salk vaccine.
 
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/> 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 |author=Smallman-Raynor, Matthew |title=Poliomyelitis: A World Geography: Emergence to Eradication |publisher=Oxford University Press, USA |year=2006 |isbn=0-19-924474-X }}</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=92-75-11607-5 }}</ref> One dose of OPV produces immunity to all three poliovirus serotypes in approximately 50% of recipients.<ref name=PinkPages/> Three doses of live-attenuated OPV produce protective antibody to all three poliovirus types in more than 95% of recipients. 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/> The live virus used in the vaccine is shed in the stool and can be spread to others within a community. IPV produces less [[gastrointestinal]] immunity than does OPV, and primarily acts by preventing the virus from entering the nervous system. In regions without wild poliovirus, inactivated polio vaccine is the vaccine of choice.<ref name=Peds/> In regions with higher incidence of polio, and thus a different relative risk between efficacy and reversion of the vaccine to a virulent form, live vaccine is still used. The live virus also has stringent requirements for transport and storage, which are a problem in some hot or remote areas. As with other live-virus vaccines, immunity initiated by OPV is probably lifelong.<ref name=Robertson_1993/>
 
===Iatrogenic (vaccine-induced) polio===
A major concern about the oral polio vaccine (OPV) is its known ability to revert to a form that can achieve neurological infection and cause paralysis.<ref name=Shimizu_2004>{{cite journal |author=Shimizu H |title=Circulation of Type 1 Vaccine-Derived Poliovirus in the Philippines in 2001 |journal=J. Virol. |volume=78 |issue=24 |pages=13512–21 |date=December 2004 |pmid=15564462 |pmc=533948 |doi=10.1128/JVI.78.24.13512-13521.2004 |url=http://jvi.asm.org/cgi/pmidlookup?view=long&pmid=15564462 |author-separator=, |author2=Thorley B |author3=Paladin FJ |display-authors=3 |last4=Brussen |first4=K. A. |last5=Stambos |first5=V. |last6=Yuen |first6=L. |last7=Utama |first7=A. |last8=Tano |first8=Y. |last9=Arita |first9=M.}}</ref> Clinical disease, including paralysis, caused by vaccine-derived poliovirus (VDPV) is indistinguishable from that caused by wild polioviruses.<ref name=Cono>{{cite web| author=Cono J, Alexander LN | year= 2002 | work=Vaccine-Preventable Disease Surveillance Manual | edition=3rd | title=Chapter 10: Poliomyelitis | url= http://www.cdc.gov/vaccines/pubs/surv-manual/3rd-edition-chpt10_polio.pdf|format=PDF}}{{dead link|date=January 2013}}</ref> This is believed to be a rare event, but outbreaks of vaccine-associated paralytic poliomyelitis (VAPP) have been reported, and tend to occur in areas of low coverage by OPV, presumably because the OPV is itself protective against the related outbreak strain.<ref name=Kew_2002>{{cite journal | author = Kew O | title = Outbreak of poliomyelitis in Hispaniola associated with circulating type 1 vaccine-derived poliovirus | journal = Science | volume = 296 | issue = 5566 | pages = 356–9 | year = 2002 | pmid = 11896235 | doi = 10.1126/science.1068284 | author-separator = , | display-authors = 1 | last2 = Morris-Glasgow | first2 = V | last3 = Landaverde | first3 = M | last4 = Burns | first4 = C | last5 = Shaw | first5 = J | last6 = Garib | first6 = Z | last7 = André | first7 = J | last8 = Blackman | first8 = E | last9 = Freeman | first9 = CJ}}</ref><ref name=Yang_2003>{{cite journal |author=Yang CF |title=Circulation of Endemic Type 2 Vaccine-Derived Poliovirus in Egypt from 1983 to 1993 |journal=J. Virol. |volume=77 |issue=15 |pages=8366–77 |date=August 2003 |pmid=12857906 |pmc=165252 |doi= 10.1128/JVI.77.15.8366-8377.2003|url=http://jvi.asm.org/cgi/pmidlookup?view=long&pmid=12857906 |author-separator=, |author2=Naguib T |author3=Yang SJ |display-authors=3 |last4=Nasr |first4=E. |last5=Jorba |first5=J. |last6=Ahmed |first6=N. |last7=Campagnoli |first7=R. |last8=Van Der Avoort |first8=H. |last9=Shimizu |first9=H.}}</ref>
 
[[File:Bundesarchiv B 145 Bild-F025952-0015, Bonn, Gesundheitsamt, Schutzimpfung.jpg|thumb|left|Doses of oral polio vaccine are added to sugar cubes for use in a 1967 vaccination campaign in [[Bonn]], [[West Germany]]]]
 
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As the incidence of wild polio diminishes, nations transition from use of the oral vaccine back to the injected vaccine because the direct risk of iatrogenic polio (VAPP) due to OPV outweighs the indirect benefit of immunization via subclinical transmission of OPV. When IPV is used, reversion is not possible but there remains a small risk of clinical infection upon exposure to reverted OPV or wild polio virus. Following the widespread use of polio vaccines in the mid-1950s, the incidence of poliomyelitis declined rapidly in many industrialized countries. The use of OPV was discontinued in the United States in 2000 and in 2004 in the UK, but it continues to be used around the globe.<ref name= PinkPages/><ref name=UK/> A nine-month-old boy from Navi Mumbai tested positive for Vaccine- Derived Poliovirus (VDPV) type 2 making it fourth such case recorded in India in 2013.<ref>{{Cite news|title = Mumbai child becomes fourth Indian to get polio from vaccine|date = July 29, 2013|url = http://www.thehindu.com/news/national/other-states/mumbai-child-becomes-fourth-indian-to-get-polio-from-vaccine/article4967388.ece|newspaper = The Hindu|accessdate = 30 July 2013}}</ref>
 
The rate of vaccine-associated paralytic poliomyelitis (VAPP) varies by region but is generally about 1 case per 750,000 vaccine recipients.<ref name=Racaniello_2006>{{cite journal |author=Racaniello V |title=One hundred years of poliovirus pathogenesis |journal=Virology |volume=344 |issue=1 |pages=9–16 |year=2006 |pmid=16364730 |doi=10.1016/j.virol.2005.09.015}}</ref> VAPP is more likely to occur in adults than in children. In [[immunodeficient]] children, the risk of VAPP is almost 7,000 times higher, particularly for persons with [[B-lymphocyte]] disorders (e.g., [[agammaglobulinemia]] and [[hypogammaglobulinemia]]), which reduce the synthesis of protective [[antibodies]].<ref name= Cono/> The [[World Health Organization]] considers the benefits of vaccination to far outweigh the risk of vaccine derived polio. Outbreaks of vaccine derived polio have been stopped by multiple rounds of high-quality vaccination, in order to immunize the entire population.<ref name="who-Q&A">{{cite web | title = What is vaccine-derived polio? | publisher = WHO | date = 2007-10-08| url = http://www.who.int/features/qa/64/en/index.html | accessdate=2008-11-29 }}</ref>
 
Outbreaks of VAPP occurred independently in [[Belarus]] (1965–66), [[Canada]] (1966–68), [[Egypt]] (1983–1993), [[Hispaniola]] (2000–2001), [[Philippines]] (2001), [[Madagascar]] (2001–2002),<ref>{{cite journal |author=Kew O |title=Circulating vaccine-derived polioviruses: current state of knowledge |url= http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862004000100006&lng=en&nrm=iso&tlng=en| journal=Bull World Health Organ |volume=82 |issue=1 |pages=16–23 |year=2004 |pmid=15106296 |pmc=2585883 |author-separator=, |author2=Wright P |author3=Agol V |display-authors=3 |doi=10.1590/S0042-96862004000100006 |last4=Delpeyroux |first4=F |last5=Shimizu |first5=H |last6=Nathanson |first6=N |last7=Pallansch |first7=MA }}</ref> and in [[Haiti]] (2002), where political strife and poverty have interfered with vaccination efforts.<ref>{{cite news | last = Fox | first = Maggie | title = Polio in Haiti linked to incomplete vaccinations: Virus can mutate and kill | work = National Post (Canada) | date=2002-03-15 |url=http://www.nationalpost.com/tech/story.html?f=/stories/20020315/344776.html | archiveurl=http://web.archive.org/web/20020603174614/http://www.nationalpost.com/tech/story.html?f=/stories/20020315/344776.html | archivedate= 2002-06-03 | accessdate = 2008-11-29 }}</ref> In 2006 an outbreak of vaccine-derived poliovirus occurred in [[China]].<ref name=Liang_2006>{{cite journal | author = Liang X | title = An outbreak of poliomyelitis caused by type 1 vaccine-derived poliovirus in China | journal = J Infect Dis | volume = 194 | issue = 5 | pages = 545–51 | year = 2006 | pmid = 16897650 | doi = 10.1086/506359 | author-separator = , | author2 = Zhang Y | author3 = Xu W | display-authors = 3 | last4 = Wen | first4 = Ning | last5 = Zuo | first5 = Shuyan | last6 = Lee | first6 = Lisa A. | last7 = Yu | first7 = Jingjin}}</ref> Cases have been reported from [[Cambodia]] (2005–2006), [[Myanmar]] (2006–2007), Iran (1995, 2005–2007), Syria, Kuwait and Egypt.<ref>{{cite journal |title=Update on vaccine-derived polioviruses—worldwide, January 2006-August 2007 |journal=MMWR Morb. Mortal. Wkly. Rep. |volume=56 |issue=38 |pages=996–1001 |date=September 2007 |pmid=17898693 |url=http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5638a3.htm |author1= Centers for Disease Control and Prevention (CDC)}}</ref> Since 2005, [[The World Health Organization]] has been tracking vaccine-caused polio in northern Nigeria caused by a mutation in live oral polio vaccines.<ref>{{cite news |url=http://www.cbsnews.com/stories/2009/08/14/health/main5242168.shtml |title= Mutant polio virus spreads in Nigeria |date=August 14, 2009 |accessdate= 2009-08-16 |work=CBS News }}</ref>
 
== Contamination concerns ==
In 1960, it was determined that the [[rhesus monkey]] kidney cells used to prepare the poliovirus vaccines were infected with the [[SV40]] virus (Simian Virus-40).<ref name=SV>{{cite web| title = Simian Virus 40 (SV40), Polio Vaccine, and Cancer | work = Vaccine Safety | publisher = Centers for Disease Control| date = 2004-04-22 | url = http://web.archive.org/web/20130522091608/http://www.cdc.gov/vaccinesafety/updates/archive/polio_and_cancer_factsheet.htm | accessdate = 2013-05-22}}</ref> SV40 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 |author=Eddy B, Borman G, Berkeley W, Young R |title=Tumors induced in hamsters by injection of rhesus monkey kidney cell extracts |journal=Proc Soc Exp Biol Med |volume=107 |pages=191–7 |year = 1961 |pmid = 13725644}}</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's lymphoma]].<ref>{{cite journal |author=Carbone M |title=Simian virus 40 and human tumors: It is time to study mechanisms |journal=J Cell Biochem |volume=76 |issue=2 |pages=189–93 |year=1999 |pmid = 10618636 |doi=10.1002/(SICI)1097-4644(20000201)76:2<189::AID-JCB3>3.0.CO;2-J}}</ref><ref>{{cite journal |author=Vilchez R, Kozinetz C, Arrington A, Madden C, Butel J |title=Simian virus 40 in human cancers |journal=Am J Med |volume=114 |issue=8 |pages=675–84 |year=2003 |pmid=12798456 |doi=10.1016/S0002-9343(03)00087-1}}</ref> However, it has not been determined that SV40 causes these cancers.<ref name= Engels>{{cite journal |author=Engels E |title=Cancer risk associated with receipt of vaccines contaminated with simian virus 40: epidemiologic research |url=http://dceg.cancer.gov/pdfs/engels41972005.pdf |format=PDF|journal=Expert Rev Vaccines |volume=4 |issue=2 |pages=197–206 |year=2005 |pmid=15889993 |doi=10.1586/14760584.4.2.197}}{{dead link|date=January 2013}}</ref>
 
SV40 was found to be present in stocks of the injected form of the polio vaccine (IPV) in use between 1955 to 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 to 1963 when a proportion of vaccine was contaminated with SV40; it has been estimated that 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 web |author= Bookchin D| title = Vaccine scandal revives cancer fear | publisher = New Scientist | date = 2004-07-07 |url=http://www.newscientist.com/news/news.jsp?id=ns99996116| archiveurl = http://web.archive.org/web/20040720074452/http://www.newscientist.com/news/news.jsp?id=ns99996116| archivedate=2004-07-20 | accessdate = 2008-11-29 }}</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 that there was no increased incidence of cancer in persons who may have received vaccine containing SV40.<ref name=Strickler_1998>{{cite journal |author=Strickler H, Rosenberg P, Devesa S, Hertel J, Fraumeni J, Goedert J |title=Contamination of poliovirus vaccines with simian virus 40 (1955-1963) and subsequent cancer rates |journal=JAMA |volume=279 |issue=4 |pages=292–5 |year=1998 |pmid=9450713 |doi=10.1001/jama.279.4.292 |url=http://jama.ama-assn.org/cgi/content/full/279/4/292}}</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 |author=Olin P, Giesecke J |title=Potential exposure to SV40 in polio vaccines used in Sweden during 1957: no impact on cancer incidence rates 1960 to 1993 |journal=Dev Biol Stand |volume=94 |pages=227–33 |year=1998 |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/>
 
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 were 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 |author=Plotkin SA |title=CHAT oral polio vaccine was not the source of human immunodeficiency virus type 1 group M for humans|journal=Clin. Infect. Dis. |volume=32 |issue=7 |pages=1068–84 |year=2001 |pmid=11264036 |doi=10.1086/319612 |last2=Modlin |first2=J. F. |last3=Plotkin |first3=S. A.}}</ref><ref name=Kowproski5>{{cite journal |author=Koprowski H |title=Historical Aspects of the Development of Live Virus Vaccine in Poliomyelitis |journal=Br Med J |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 | last = Collins | first = Huntly |title = The Gulp Heard Round the World | pages = Section D, page 1 |publisher = Philadelphia Inquirer |date = 2000-11-06 | url=http://www.koprowski.net/Polio+Article.htm|archiveurl = http://web.archive.org/web/20040405233046/http://www.koprowski.net/Polio+Article.htm | archivedate=2004-04-05 | accessdate = 2008-11-29 }}</ref> and [[OPV AIDS hypothesis|accusations in the 1990s]] arose that the vaccine had created the conditions necessary for transmission of [[Simian immunodeficiency virus|SIV]] from [[chimpanzee]]s to humans, causing [[HIV/AIDS]]. These hypotheses have, however, [[Hilary Koprowski#AIDS hypothesis|been refuted]] in some studies.<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. However, recent opposition to vaccination campaigns has evolved,<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/africa/2070634.stm |publisher=BBC News | work=Africa | title=Nigeria Muslims oppose polio vaccination |date=2002-06-27 |accessdate=2008-11-29}}</ref><ref>{{cite news |author= Dugger CW, McNeil DG | url=http://www.nytimes.com/2006/03/20/international/asia/20polio.html?pagewanted=2 |title=Rumor, Fear and Fatigue Hinder Final Push to End Polio | publisher=New York Times |date=2006-03-20 |accessdate=2008-11-29}}</ref> often relating to fears that the vaccine might induce [[Infertility|sterility]].<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/africa/4539757.stm |publisher= BBC News | work= Africa | title= Anti-polio vaccine Malians jailed |date=2005-05-12 |accessdate=2008-11-29}}</ref> The disease has since resurged in [[Nigeria]] and in several other African nations, which [[epidemiologist]]s believe is due to refusals by certain local populations to allow their children to receive the polio vaccine.<ref name=Jegede>{{cite journal |author=Jegede AS |title=What Led to the Nigerian Boycott of the Polio Vaccination Campaign? |journal=PLoS Med. |volume=4 |issue=3 |pages=e73 |date=March 2007 |pmid=17388657 |pmc=1831725 |doi=10.1371/journal.pmed.0040073 |url=http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0040073}}</ref>
 
== References ==
{{Reflist|30em}}
 
== External links ==
* [http://www.historyofvaccines.org/content/timelines/polio History of Vaccines Website – History of Polio] History of Vaccines, a project of the [[College of Physicians of Philadelphia]]
* [http://blogs.cgdev.org/vaccine CGDev.org] — 'Vaccines for Development', [[Center for Global Development]]
* [http://www.pbs.org/wgbh/aso/databank/entries/dm52sa.html PBS.org] — 'People and Discoveries: Salk Produces Polio Vaccine 1952', [[Public Broadcasting Service|PBS]]
*[http://www.smithsonianmag.com/science-nature/polio.html Conquering Polio], Smithsonian Magazine, April 2005
*[http://www.vigyanprasar.gov.in/dream/apr2004/english.pdf The Global Effort To Eradicate Polio], Dream 2047 Magazine, April 2004
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