Pakistan launched a nationwide polio vaccination drive on Monday to try to reach 38.7 million children and eradicate the paralysing and potentially deadly virus in one of the last countries where it is endemic.
Nearly 260,000 volunteers and workers fanned out across Pakistan in an effort to vaccinate every child below the age of five in a week-long campaign, Pakistan's national coordinator on polio, Mohammad Safdar, said.
"We're really very close to eradicating the disease," Safdar told Reuters, appealing to the people to cooperate with the door-to-door effort.
Pakistan is one of only three countries in the world, along with Afghanistan and Nigeria, that suffers from endemic polio, a childhood virus that can cause paralysis or death.
In 2018, Pakistan has had just one polio case, reported last month, Safdar said. The number of cases has steadily declined since 2014 when 306 were reported. Last year, there were only eight cases, he said.
Efforts to eradicate the disease have been undermined by opposition from the Taliban and other militants, who say immunisation is a foreign ploy to sterilise Muslim children or a cover for Western spies.
In January, gunmen killed a mother-and-daughter vaccination team working in the southwestern province of Baluchistan, where the year's only case so far was later reporter.
Three years earlier, 15 people were killed in a bombing by the Pakistani Taliban outside a polio vaccination centre in Baluchistan.
Polio teams working on Monday were undeterred.
"Yes we feel threatened, but our work is like this," said Bilquis Omar, who has served on a mobile vaccination team for the past six years in the southern port metropolis of Karachi.
"We are working for the children," she said.
Aziz Memon, who heads the Rotary Club's Polio Plus programme that funds many of the immunisation teams, said this year the drive was also making a renewed effort to reach migrants who come back and forth from Afghanistan.
"Mission number one is to get to zero cases and eradicate polio," Memon said.
A country must have no cases for three consecutive years in order to be considered to have eradicated polio by the World Health Organisation.
Pakistan has to contend with extra suspicion of immunisation drives because of the 2011 US special forces raid inside the country that killed al Qaeda leader Osama bin Laden, architect of the September 11 attacks on the United States in 2001.
A Pakistani doctor was accused of using a fake vaccination campaign to collect DNA samples that the CIA was believed to have been using to verify bin Laden's identity. The doctor remains jailed in Pakistan, convicted of waging war against state.