Taliban leaders in Pakistan are blocking a polio vaccination campaign that was to target 161,000 children in North Waziristan.

The Taliban commander Hafiz Gul Bahadur is demanding that the US Central Intelligence Agency (CIA) halt drone strikes, which have heavily targeted the mountainous region, according to a story in the New York Times. The move could prove a setback for the global initiative to eradicate polio, which aims to stop polio transmission globally by the end of 2012 but is unlikely to meet that deadline. (see ‘Polio’s last stand‘)

Drone strikes have increased in number over the past two years, and just two weeks ago, Al Qaeda’s number two, Abu Yahya al-Libi, was reportedly killed in North Waziristan by drones.

Along with Nigeria and Afghanistan, Pakistan is one of three countries never to have stopped polio from spreading. After an upsurge in cases in 2011, polio cases are at an all time low in Pakistan this year, with just 22 recorded so far, compared to 52 at this time last year.

There have been no cases of polio detected in Waziristan this year. But the region, which is part of the Federally Administered Tribal Areas, borders Afghanistan and faces security issues that have hindered vaccination campaigns in the past.

Unicef told the Times that 143,000 of North Waziristan’s 161,000 children under the age of 5 received an oral polio vaccination during a campaign earlier this month. However, several rounds of the oral vaccine are needed to prevent the virus from spreading.

Sona Bari, the spokesperson for the Global Polio Eradication Initiative, tells Nature that Pakistan faces a bevy of accountability problems in its efforts to wipe out polio. “I don’t think access to children in North Waziristan is why polio is not being eradicated in Pakistan.”

The Taliban commander in North Waziristan, Bahadur, said that there was a “strong possibility of spying on mujahedeen for the U.S. during the polio vaccination campaign; one such example is Dr. Shakil Afridi.”

The Pakistani physician was sentenced to 33 years in prison last month for participating in vaccination campaign with the goal of obtaining DNA from children living in the Abottabad compound believed to house Osama bin Laden. Public support for and uptake of vaccinations in the Federally Administered Tribal Areas fell dramatically after news of the campaign, rumoured to be sponsored by the CIA, broke in summer 2011, according to a Vaccine Confidence Index maintained by researchers at the London School of Hygiene and Tropical Medicine.

Image courtesy of Global Polio Eradication Initiative/World Health Organization