For years, Africans have spread rumors that vaccines were the Western world’s means to sterilize Africans or give them AIDS. Now, the oral polio vaccine is giving Nigerians polio, because the attenuated virus has mutated back into the deadly form:
This year, the number of polio cases caused by the vaccine has doubled: 124 children have so far been paralyzed, compared to 62 in 2008, out of about 42 million children vaccinated. For every case of paralysis, there are hundreds of other children who don’t develop symptoms, but pass on the disease.When Nigerian leaders suspended polio vaccination in 2003, believing the vaccine would sterilize their children and infect them with HIV, Nigeria exported polio to nearly two dozen countries worldwide, making it as far away as Indonesia.
Nigeria resumed vaccinations in 2004 after tests showed the vaccine was not contaminated with estrogen, anti-fertility agents or HIV.
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The oral polio vaccine used in Nigeria and elsewhere contains a mild version of the live virus. Children who have been vaccinated pass the virus into the water supply through urine or feces. Other children who then play in or drink that water pick up the vaccine’s virus, which gives them some protection against polio.But in rare instances, as the virus passes through unimmunized children, it can mutate into a strain dangerous enough to ignite new outbreaks, particularly if immunization rates in the rest of the population are low.
Kew said genetic analysis proves mutated viruses from the vaccine have caused at least seven separate outbreaks in Nigeria.
Though Nigeria’s coverage rates have improved, up to 15 percent of children in the north still haven’t been vaccinated against polio. To eradicate the disease, officials need to reach about 95 percent of the population.