Pakistan, April 21 -- Three hundred thousand children missed in Pakistan's second nationwide polio campaign should not and cannot be dressed up as a manageable shortfall. The campaign set out to reach more than 45 million children and fell short at 44.7 million, leaving a gap that officials say stems from refusals, mobility and access.

It is lower than the nearly one million missed in the February drive, yes, but that is hardly a standard fit for a country still carrying one of the world's last reservoirs of wild poliovirus. Pakistan recorded 31 cases last year and has already confirmed another this year. The virus is still showing up in sewage, still moving through Karachi, still entrenched in South Khyber Pakhtunkhwa, still waiting for...