[jinx]

Polio vaccine causing polio outbreaks in Nigeria.

LONDON - Polio is spreading in Nigeria and health officials say in some cases it's caused by the vaccine used to fight the paralyzing disease.

In July, the World Health Organization issued a warning that this particular virus might extend beyond Africa. So far, 124 Nigerian children have been paralyzed this year — about twice those afflicted in 2008.


Nigeria and most other poor nations use an oral polio vaccine because it's cheaper, easier, and protects entire communities. But it's made from a live polio virus which carries a small risk of causing polio. In even rarer instances, the virus in the vaccine can mutate into a deadlier version that ignites new outbreaks.


A virologist with the U.S. Centers for Disease Control and Prevention says genetic analysis proves such mutated viruses have caused at least seven separate outbreaks in Nigeria.