PESHAWAR, Pakistan (AFP) — Gunmen in northwest Pakistan killed two police officers protecting polio vaccination workers on Monday, a security official said, on the first day of a nationwide campaign to counter rising cases.

Pakistan is one of two countries, along with Afghanistan, where polio remains endemic, but militants have killed hundreds of police officers and health workers over the past decade as part of a campaign against the Pakistani state.

“During the polio campaign in the tribal district of Bajaur District, two police officials assigned to protect vaccination teams were shot dead by motorcycle-riding militants in two separate attacks,” a senior security official based in Peshawar told Agence France-Presse.

The official added that “terrorists gunned down two more policemen” performing routine duties in Kohat and Dera Ismail Khan.

The attacks come as Pakistan kicked off a week-long polio vaccination campaign in 79 high-risk districts in which more than 19 million children will be administered polio drops.

Polio, a highly infectious virus mainly affecting children under five, can result in lifelong paralysis but is easily prevented by the oral administration of a few drops of a vaccine.

There is a raft of misinformation circulating about the vaccine in rural Pakistan, including that it is a Central Intelligence Agency plot to stop Muslims from having children.