Three-year-old Farid Ahmad teeters forward, his uncle hovering closely behind.

“He is so weak, mainly his hands and legs,” Abdul Jalil says, watching as the boy roams unsteadily inside the family’s compound here in Spin Boldak District, which stretches to the Pakistan border in southern Afghanistan’s Kandahar Province. “Sometimes when he tries to walk, he falls down.”

This week, Afghan authorities launched a new round of polio immunisations – the second nationwide campaign this year. They hope to reach more than 9.9 million children across the country with oral vaccines before the start of the polio “high season” in the warmer summer months, when the virus is most infectious.

The front line of the push to wipe out polio runs through places like Kandahar. Here, hard-fought progress is fragile and easily jeopardised by mistrust, missed vaccinations, out-of-reach healthcare, a dearth of female healthcare workers, and pockets of insecurity – where access for vital immunisation programmes must be negotiated with militant groups like the Taliban.

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