Yet another campaign

This week's launch of yet another nationwide polio vaccination campaign in Pakistan - targeting some 45 million children under five across 159 districts - is another reminder of both ambition and frustration in the country's struggle to eradicate the disease. While door-to-door teams of more than 400,000 workers will be dispatched, the fact that roughly 830,000 children are still missed in each campaign is a troubling statistic that underlines an endemic weakness in implementation. It is not enough to repeat mass drives, hoping for incremental gains. The persistence of polio, even in tiny pockets, suggests that the strategy has reached diminishing returns. Environmental detection of poliovirus in multiple districts and confirmed new human cases signal that we are not closing the gaps fast