Women walk past the polio vaccine dispensary in Kano, Nigeria, where gunmen killed female health workers last Friday.
Aminu Abubakar/AFP/Getty Images
The attack in Nigeria come just on the heels of similar ones in Pakistan, when gunmen killed at least eight people involved in anti-polio campaigns in December. That violence prompted the United Nations to suspend its vaccination campaigns in Pakistan.
As deadly attacks on polio vaccinators are escalating, the number of new polio cases has dropped dramatically.
In 2011, there were 716 polio cases reported worldwide. Last year that number decreased to 222. And the virus is now endemic in only three countries: Nigeria, Pakistan and Afghanistan.
So far this year, the tally is just one case, according to the World Health Organization. This is the lowest rate of polio ever seen and could indicate that the disease is on its last legs.
The one case has occurred in Karachi, Pakistan. The newspaper Dawn reported that a 2-year-old boy became infected after his family repeatedly refused the polio vaccine during immunization drives because they "had old misconceptions about polio vaccination."
Rumors persist in Pakistan and Nigeria that the polio vaccine is a Western plot by the CIA to sterilize Muslim children.
A decade ago, such rumors led Nigeria to suspend polio vaccination campaigns for almost a year. That in turn sparked an explosion of polio cases, not just in Nigeria, but in 20 other countries that previously had been declared polio-free.
Nigerian President Goodluck Jonathan says the attack this month on the health workers will not derail polio eradication efforts. "The Federal Government will ensure that the mission to totally eradicate polio from Nigeria ... is carried out to a very successful conclusion," he said.
So far, no one has claimed responsibility for the attacks in Kano, Nigeria. But the AP reported that witnesses believe the radical Islamic group Boko Haram, which is currently locked in a bloody, guerilla war against the Nigerian government, was responsible.
Boko Haram operates throughout northern Nigeria, and Kano is one of its key battlegrounds. Late last month, the group attempted to assassinate the top Muslim cleric in Kano. The Emir of Kano, Ado Bayero, has been a vocal supporter of the polio-immunization efforts.