Panic in Pakistan as rumors spread that children are dying from contaminated polio vaccines.
The source of the rumors - religious hardliners in the city of Peshawar.
Last week it came to violence.
Mobs attacked a village health center leaving medical workers fearing for their lives.
There is no known cure for polio, which can cause paralysis and even death, although it can be prevented if children are given multiple treatments with the vaccine.
But fear is thwarting government inoculation drives.
Most of the 33 polio cases recorded by the World Health Organization last year were in Pakistan or neighboring Afghanistan.
(SOUNDBITE) (Pashto) LOCAL RESIDENT ZAHIR KHAN, SAYING: "No more vaccines!
My son said: 'The next time they bring polio drops, I am going to run away.'
I said: 'Do that.'
" The problem goes back years to claims by some clerics that polio vaccines are part of a Western plot to make Muslims sterile.
Militant groups have killed nearly 100 health workers and their guards in recent years, three just last week.
Nadia Gul is one of the volunteers putting her life on the line.
(SOUNDBITE) (Urdu) POLIO VACCINATOR NADIA GUL, SAYING: "Our aim, the aim of all the polio workers, is that we wipe this scourge from our country so that no child, God forbid, is crippled." Killings have escalated before, when a doctor fighting polio helped U.S. forces track down and eliminate al Qaeda leader Osama bin Laden in 2011.
Government officials say the polio vaccine backlash is bigger than ever They're worried that the suspicions of a hardline minority are infecting the wider public.
(SOUNDBITE) (English) PAKISTAN GOVERNMENT'S FOCAL PERSON ON POLIO, BABAR ATTA, SAYING: "Community mistrust in one segment of society which refused vaccination due to religious beliefs will translate into the rest of the country, is something not seen in the past." Officials say there have been no confirmed deaths from the polio vaccine But last week, rumors triggered a rush on hospitals in Peshawar with some 45,000 children complaining of nausea and dizziness.
Among the crowds people were seen passing around syringes containing a so-called antidote.
Officials call it mass hysteria and say 1.4 million children missed out on last month's inoculation drive due to the panic.
They're now going after the perpetrators and have arrested at least 17 people.
Meanwhile, health workers like Nadia Gul say they're aware of the public anger but have no plans to stop.