Retaliation could risk drawing the country, which is already mired in political and economic crises, into Middle East upheaval that it has so far avoided.
Tensions have been rising between Pakistan and Afghanistan, and violence in the border area has increased since Pakistan directed all undocumented foreigners to leave the country.
The former prime minister accused military and government officials of plotting the attack that wounded him as political violence welled up around Pakistan.
An inoculation push, plagued with limited supplies and red tape, makes doses available to those who can pay for them. In a country with a struggling economy, most can’t.