India's Last Wild Polio Case Was Reported in Howrah on 13 January 2011, and the Pulse Polio Campaign Behind It Led to WHO Certifying South-East Asia Polio-Free on 27 March 2014

India’s last case of wild polio was reported on 13 January 2011, in a two-year-old girl in Howrah, West Bengal. On 27 March 2014 the WHO South-East Asia Region, which has 11 countries and includes India, was declared free of wild poliovirus, and India was the last country in the region to stop transmission. The campaign behind that result began in Delhi on 2 October 1994, when India had around 60 percent of the world’s polio cases, according to WHO India.

The figures below come from Union Health Ministry releases carried by the Press Information Bureau (PIB), from WHO, and from reports by the US Centers for Disease Control and Prevention (CDC). Where they disagree, each figure is credited to its source.

A Sunday in Delhi, 2 October 1994

Pulse Polio is a supplementary immunisation campaign. On a fixed day, children under a set age are offered oral polio vaccine drops at booths, in addition to the doses in the routine schedule. The first one ran in Delhi on 2 October 1994, Mahatma Gandhi’s birth anniversary. PIB’s 2019 release on the programme’s 25th year says it reached nearly 1.2 million children up to the age of three, with doses on 2 October and 4 December 1994, all given through booths.

Dr Harsh Vardhan, then Delhi’s health minister and later Union Health Minister, piloted the round. Recalling it in 2021, he said almost 12 lakh children were immunised in a single day at around 4,000 centres, and that the strategy had been conceived in December 1993. Its slogan, Do Boond Zindagi Ki (“two drops of life”), became synonymous with the national effort, PIB’s 2024 backgrounder says.

Sources date the national programme differently. WHO India says Pulse Polio was rolled out on 2 October 1994. PIB’s March 2026 backgrounder says it was launched in 1995, and that National Vaccination Day on 16 March marks the first dose of oral polio vaccine given under it that year.

How many cases there were, and why the counts differ

The size of the problem depends on the source. The Global Polio Eradication Initiative’s India fact sheet, prepared in January 2012, says an estimated 150,000 polio cases occurred each year when Pulse Polio launched in 1995. The same sheet lists 6,028 reported cases for 1991. A CDC report from 2011 puts the 1995 figure at an estimated 50,000 cases a year. A 2013 review in the Indian Journal of Medical Research, by John Jacob and Vipin Vashishtha, says polio was hyperendemic until the early 1990s, with 200,000 to 400,000 cases a year.

Reported counts were much lower than any of these. CDC’s 1996 report gives 2,993 reported cases for 1995, and its 1998 report lists 3,263 for the same year. Estimates and reports measure different things, and the published numbers do not reconcile.

National surveillance for paralysis cases began in April 1997. Virus-confirmed cases were 1,934 in 1998 and 1,126 in 1999, CDC’s regional report says, and the 2013 review puts the wild-virus cases at 265 in 2000 and 268 in 2001.

From 87.8 million children in the first round to 172 million by 2011

The first two nationwide rounds, in December 1995 and January 1996, vaccinated 87.8 million and 93.6 million children, about nine in ten of them under three, CDC’s report on those rounds says. About 500,000 vaccination posts were open, and nearly 2 million health workers and volunteers took part. Each post had at least one trained health worker and at least three volunteers. From 1996 the target group became all children under five, the 2013 review notes.

The rounds grew. The December 1997 and January 1998 rounds vaccinated 127 million and 134 million children. One round in 1999 reached 147 million, which CDC’s regional report described as the largest public health campaign ever run in a single country.

Until 1998 and 1999 the rounds were booth-based, two a winter, six weeks apart. From 2000 each round was followed by house-to-house searches for children who had been missed. PIB’s 2021 and 2022 releases give the follow-up window as the next two to five days. By 2011, the GPEI fact sheet says, each national round sent nearly 2.3 million vaccinators under 155,000 supervisors to 209 million houses to reach around 172 million children under five.

Recent rounds have a similar shape. PIB’s launch release for January 2021 planned for around 17 crore (170 million) children, about 24 lakh volunteers, 1.5 lakh supervisors and visits to as many as 2 crore households. WHO India’s April 2021 account counts close to 700,000 booths, around 1.2 million vaccinators and 180,000 supervisors on that Polio Ravivar (Polio Sunday), and reports more than 159 million children vaccinated since January against a target of 165 million. The 2022 round, launched on 26 February, was planned for over 15 crore children in 735 districts of all 36 states and union territories, with drops at 7 lakh booths.

Keeping the drops cold

Oral polio vaccine is damaged by heat. A 2012 paper in the Indian Journal of Medical Research notes that the vaccine is conventionally stored below 8 °C and advises that the cold chain be kept up until the dose is given. Each vial carries a vaccine vial monitor, a label that records the heat the vial has been exposed to. The same paper notes that summer temperatures in Uttar Pradesh, Bihar and Rajasthan routinely reach 45 °C and sometimes 50 °C, and cites half-lives for the vaccine virus of 14 hours at 45 °C and 3 hours at 50 °C.

CDC’s report on the first national rounds records that a survey on 9 December 1995 found the cold chain well maintained. PIB’s 2024 backgrounder credits the National Cold Chain Training Centre and the Electronic Vaccine Intelligence Network with better storage and distribution of vaccines across India’s immunisation programme. The 2013 review adds that the stool samples of children with paralysis went to laboratories under cold chain conditions too. For how a vaccine batch is tested and released before it reaches a cold box, see how Indian vaccine makers make and release a batch.

Teams at the stations

A booth in a home district does not reach a child at a railway station. The 2013 review notes that large numbers of people migrate for seasonal work and that their children often missed doses, and describes a transit strategy introduced after 2004, with teams stationed at bus stands, railway stations, highways and markets.

CDC’s 2014 report says transit teams vaccinated nearly 10 million children in each campaign, more than 100,000 of them on trains. The GPEI fact sheet counts around 5 million children a round reached by transit and mobile teams in Uttar Pradesh, Bihar and Mumbai alone, and lists construction sites among their stops. The two figures cover different areas and do not conflict. In 2022 PIB listed vaccination teams at bus terminals, railway stations, airports and ferry crossings.

The network that looked for every case

A campaign needs a way to find out whether it is working. India built one around acute flaccid paralysis (AFP), the sudden weakness in a child under 15 that polio can cause. The Government of India and WHO set up the National Polio Surveillance Project (NPSP) in 1997, a 2024 review in the journal Vaccines says, along with a polio laboratory network. The 2013 review places the design of the project in 1995, by WHO, UNICEF, the CDC and Rotary International, so the sources differ by two years on when it began.

The numbers show the reach. By October 1997, 59 surveillance medical officers were posted to support 556 districts, according to CDC. In 2012 India’s rate of paralysis cases not caused by polio was 13.9 per 100,000 children under 15, and 87 percent of cases had adequate stool samples. The 2013 review gives the global benchmark for adequate surveillance as at least one such case per 100,000 children. Eight accredited laboratories tested the samples. Sewage testing began in Mumbai in 2001, in Delhi in 2010, and in Patna and Kolkata in 2011. The last wild poliovirus found in sewage was in Mumbai in November 2010.

CDC’s 2014 report says local Rotary members provided volunteers and funding, and lists WHO, UNICEF, the Bill and Melinda Gates Foundation, the World Bank and several governments among the partners. PIB’s 2024 backgrounder names the Government of India’s partners as UNICEF, WHO, the Gates Foundation, Rotary International and the CDC. The fact sheet counts nearly 8,500 community mobilisers in Uttar Pradesh, Bihar and West Bengal, who also carry messages on hygiene, sanitation and handwashing, a subject with its own national programme in the Swachh Bharat Mission. WHO India adds that volunteers helped plan each round locally and that community and religious leaders were engaged to answer concerns.

Changing the vaccine mix

Wild poliovirus has three types, and India closed them out one at a time. The last type 2 case was in Aligarh, Uttar Pradesh, on 24 October 1999. The last type 3 case was in Pakur, Jharkhand, on 22 October 2010, and the last type 1 case was the one in Howrah on 13 January 2011, WHO South-East Asia records.

The standard three-type vaccine had not stopped types 1 and 3 in Uttar Pradesh and Bihar, even though the 2000 and 2001 rounds reached 94 to 95 percent of the children they targeted. The 2013 review concluded that close to every child had to be vaccinated, repeatedly. India added tools. Single-type vaccines for types 1 and 3 came in 2005, and a two-type vaccine in 2010, CDC’s 2014 report says, which links the main use of the two-type vaccine to falls in both type 1 and type 3 cases. The 2013 review says the single-type vaccines were licensed on an early Indian study showing they worked 2.5 to 3 times better than the three-type vaccine. Pulse rounds rose to 10 a year from 2005, it adds, and CDC notes special plans for hard-to-reach areas such as the Kosi river flood plain in Bihar.

The count did not fall in a straight line. It was around 1,600 in 2002, 676 in 2006, 874 in 2007 and 741 in 2009, according to the 2013 review and the fact sheet. Then it dropped to 42 in 2010. CDC’s 2014 report puts routine three-dose oral vaccine coverage for children aged 12 to 23 months at 70.4 percent nationally in 2009 and 2010, with Bihar at 61.6 percent and Uttar Pradesh at 53.9 percent.

The last case and the certificate

One case was reported in 2011, against 42 in 2010 and 741 in 2009. The fact sheet says 13 January 2012 would complete 12 months with no case and projected India’s removal from WHO’s list of polio-endemic countries by mid-February 2012.

Regional certification asks for more. WHO South-East Asia says it requires the absence of wild poliovirus transmission for at least three consecutive years under certification-standard surveillance, plus safe containment of laboratory stocks of the virus. On 27 March 2014 the regional certification commission declared the South-East Asia Region free of wild poliovirus, CDC reports. It was the fourth of WHO’s six regions to be certified, after the Americas in 1994, the Western Pacific in 2000 and Europe in 2002. PIB’s 2019 release says WHO called India’s result one of the most significant achievements in public health.

The work continues. India holds one national round and two sub-national rounds a year, WHO India says, and added the injectable inactivated polio vaccine to routine immunisation in 2015, according to PIB. PIB’s 2021 release notes that cases are still reported in Pakistan and Afghanistan. India marks National Vaccination Day on 16 March, the date of the first oral polio vaccine dose given under Pulse Polio in 1995, according to PIB’s March 2026 backgrounder.