It all started with a rumor, a panting video circulating on Facebook saying that the children in Peshawar had fallen ill after being vaccinated against poliomyelitis.
Within hours, a second video emerged showing the same children being instructed to lie down and pretend illness. But it was too late. The latest attempt to cripple Pakistan's efforts to eradicate polio had already taken place, leaving thousands of parents in a state of panic and a partially burned-out health facility.
The man who orchestrated the alarmist video was arrested, but Babar Bin Atta, the prime minister's focal point for polio eradication, was clearly exasperated.
"The man is a troublemaker caught red-handed on video telling kids to act like they were sick," he said. "The real enemy is social media."
With three days to reach more than 9,000 children in the Mustafabad district of Karachi, workers going from door to door are frustrated at having to deal with yet another whirlwind of misinformation. However, armed with essential vaccine drops and baby vitamins – not to mention facts, smartphone videos and endorsements from doctors, clergymen and celebrities that have become an essential part of attempts to eradicate secular disease in Pakistan – they remain resolute.
Across the country, a quarter of a million frontline workers are involved in efforts to vaccinate the 40 million children in the country under the age of five. Zahoor Jah, 55, a grandfather who lives in the area, says that repeated impulses can be tedious, especially in areas that are not well attended by health clinics. But he expects polio to follow the path of smallpox.
"It's a lack of education that leads to such things," he says of the Peshawar videos. "But these women are doing a fantastic job of convincing just about everyone. Being local makes a big difference. They all recognize and trust them. "
Across the city, Syeeda Bahuu, 40, is involved in vaccination efforts at Karachi Cantonment, the city's main railway station. Originally from Quetta, she moved south to Karachi after "some trouble". Two of his own children were affected by poliomyelitis. A typical change brings 700 rupees (7.61 pounds) a day.
Although most children are vaccinated at home, the presence of staff here and the number of people in the city reflect how people's lives can be, from seasonal workers to those visiting the family. Within three hours, Bahuu converted 16 refusals into successful vaccinations, using his personal experience and videos from the city's emergency operational center. In all, 418 children were inoculated here this morning.
Polio is now endemic in just three countries: Pakistan, Afghanistan and Nigeria. Pakistan is temptingly close to eradication. The number of cases here dropped from 306 in 2014 to 13 so far this year, but environmental testing shows that the virus is still present in the country.
Naeemjan Barki was devastated when his son was diagnosed with poliomyelitis. Now 11, Naseebullah likes to hang out with his father to support the vaccination teams in the volatile Gulshan Town. He loves cricket, but says not everyone will play with him. Naseebullah seizes the opportunity to get in touch with Jim Bailey, who is visiting Karachi with the One Last Push campaign.
At age 62, Bailey is a member of the latest British generation living with the long-term effects of polio. A former taxi driver from Falls Road in Belfast, he now teaches IT skills to those who drop out of school.
He is here in Karachi to see "how they are dealing with what we left in the past." Bailey is impressed by the resilience of those affected.
"It's a huge show going on here," he says. "I suppose I thought," I have polio, that's it, done and dusted, I do not have to worry about it anymore. "But polio can come back. It can affect my children, my grandchildren, unless It is incredible the effort that the vaccinators have to do here, they can not fail.
Gulnaz Shirazi, 35, ensures that every child entering the social security hospital in the Landhi industrial area of the city is vaccinated. Your skillful controls are fueled by personal involvement. In 2012, when she finished the day, she heard the shots that killed her sister-in-law and niece, both polio prevention agents, a few streets away. "I decided that I could not let their lives be wasted. It just made my determination stronger.
Khalida Nasareen, 61, got involved for the first time 22 years ago when she was a local councilor in the city of Orangi, in the north of the city. She has been instrumental in recruiting women from the community who have the right skills, education, trust, and access. Two health professionals were killed in the area in 2012, and it was not easy to persuade parents to allow their daughters to vaccinate from street to street for 7,500 rupees.
"There was a lot of fear, but that has improved since the community-based approach has taken off," she says.
"We build relationships with families by listening to their problems, getting to know them. We can see the extra pair of shoes on the door that belongs to a visiting child.
Now 61, she started to get around quad biking so she can be quickly on site if one of her team calls with problems. Your diabetes means that it has numbness in one foot, but nothing will stop it. "You can not close the program until polio is eradicated," she says. "No small child should catch the virus nowadays."