Paris

A boycott by two Nigerian states of an immunization campaign by the World Health Organization-led Global Polio Eradication Initiative could jeopardize its goal of eradicating the disease by the end of this year.

Kano and Zamfara states refused to take part in a February campaign by the World Health Organization (WHO) in west and central Africa that aimed to immunize 63 million children. Muslim clerics there have claimed that the vaccines are contaminated with contraceptives, carry HIV and are a Western plot against their populations.

Some community leaders are also saying that the vaccine causes AIDS, having picked up on an international debate over the now-refuted claim that it was the origin of the AIDS virus (see Nature 404, 9; 2000). “If you search for ‘polio vaccine’ on the Internet you find a lot of stuff — not all of it good,” says Oliver Rosenbauer, a WHO spokesman.

Such claims led several states in northern Nigeria to boycott a WHO campaign in August. Since then the federal government has backed immunization, and in October, the Organization of the Islamic Conference, which represents 56 Muslim nations, gave its support to the polio-eradication initiative.

But two uncooperative states is still two too many, warns Rosenbauer, who says that eradication must take place in all territories. The virus must be eliminated wherever it remains, he warns, as a single case could spawn an outbreak.

Indeed, last summer's boycott by several of Nigeria's northern states is seen as responsible for the country having the largest number of new polio cases — 347 from the start of 2003 to February 2004, nearly half of all new cases worldwide. It is also blamed for 20 new polio cases in recent months in 8 previously polio-free African countries: Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Côte d'Ivoire, Ghana and Togo.

Nigeria has since set up joint team of scientists and community leaders to look at the vaccine's safety. It is expected to release its report officially later this month. WHO officials are optimistic that this will be in time for the two states to consider their position ahead of the next round of immunization in late March.

“All the indications are that the tests have proved negative for any harmful or suspicious agents, and in particular, none of those allegedly capable of promoting birth control were detected,” says Idris Mohammed, chairman of Nigeria's National Programme on Immunization.

But even if all Nigerian states comply, the publicity surrounding the rumours has sown seeds of doubt about polio vaccination among some community leaders. To what extent this affects the latest campaign will only become known later this month, when an analysis of data coverage is completed.

→ http://www.polioeradication.org