That Monday marked the start of an ambitious, three-day vaccination drive aimed at inoculating some 34 million Pakistani children against polio, the crippling disease eradicated in almost the entire world, yet still transmitted there.
But that day also marked the start of a determined campaign of murder — at least nine people were killed — against the very health workers trying to save children's lives.
It was a campaign rooted in a belief that these workers are out to harm the children they are trying to inoculate. Such misinformation is actively encouraged by Sunni Muslim extremists like the Pakistan Taliban, the presumed culprit in the attacks, though the group denies involvement.
Ultimately, the mistrust hurts children in some of Pakistan's most vulnerable and hardest to reach communities — and threatens to spread the harm far beyond by keeping the poliovirus alive.
Frustrated by the attacks, and the halting progress towards what the UN calls the "historic goal" of eradicating polio worldwide, the World Health Organization has now turned to one of Sunni Islam's highest authorities for advice and help.