Progress toward poliomyelitis eradication--Nigeria, January 2004-July 2005.

After the 1988 World Health Assembly resolution to eradicate polio, the number of countries where polio is endemic decreased from 125 in 1988 to six in 2003. However, the Global Polio Eradication Initiative faced critical challenges during 2003-2005, when a resurgence of polio cases occurred across Africa. Nigeria, the most populous country of the continent, experienced increased wild poliovirus (WPV) transmission throughout the country after suspension of supplementary immunization activities (SIAs) in certain northern states because of misconceptions regarding vaccine safety. The resurgence in Nigeria resulted in the spread of WPV during 2003-2005 into 18 countries that had been polio-free for 1 or more years, including three countries outside Africa. Transmission was reestablished and is ongoing in six of these countries. The Nigerian states that suspended campaigns subsequently resumed SIAs in 2004, in synchrony with SIAs being conducted in other countries across West and Central Africa. This report summarizes polio eradication activities and WPV circulation in Nigeria during January 2004-July 2005 and the actions under way to interrupt WPV transmission.