A ceremony in Nigeria has marked the start of a massive, 23-nation polio immunization drive. Health officials across sub-Saharan Africa aim to immunize 80 million children in five days against the crippling disease.

The region faces the threat of a major polio outbreak. While eradication efforts have made tremendous progress in most of the world, ninety percent of the polio cases this year are in sub-Saharan Africa. And over the last year and a half, the virus has spread from Nigeria to 12 formerly polio-free countries.

The virus spread from northern Nigeria after officials in Kano state banned the vaccine amid rumors it contained chemicals designed to depopulate the Muslim world. But governor of neighboring Kaduna state Ahmed Mohammed Makarfi says if polio has been eradicated safely in Egypt, Lybia, and Saudia Arabia, then it can be done in Nigeria as well.

Governor Makarfi says, "It has been confirmed there is nothing wrong with the vaccine. There are no more excuses not to go ahead and kick polio out of Nigeria," he says.

Vaccinators will spread out across 23 African countries starting October 8.