Progress toward poliomyelitis eradication--Nigeria, 2005-2006.

Only four countries (Afghanistan, India, Nigeria, and Pakistan) have never experienced interruption of poliovirus transmission. Nigeria had the largest number of cases in 2006, accounting for 1,129 (56%) of the 2,002 cases reported globally. However, major innovations to the national polio-eradication program in Nigeria were initiated in 2006. These innovations, if sustained, should advance the Global Polio Eradication Initiative. Nigeria (2006 population: 140 million) experienced a resurgence in wild poliovirus (WPV) transmission during 2003-2004 after a loss of public confidence in oral polio vaccine (OPV) and suspension of supplementary immunization activities (SIAs) in certain northern states. Subsequently, WPV spread within Nigeria and into 19 polio-free countries. Even after national SIAs recommenced, limited acceptance and ongoing operational problems resulted in low vaccination coverage and continued poliovirus transmission. The number of confirmed polio cases in Nigeria attributed to both WPV type 1 (WPV1) and type 3 (WPV3) increased from 782 in 2004 to 830 in 2005 and to 1,129 in 2006 (as of March 23, 2007). To increase the effectiveness of polio-eradication measures and community acceptance of vaccination, in 2006, health authorities in Nigeria introduced monovalent type 1 OPV (mOPV1) vaccine and changed the way SIAs were implemented. This report summarizes these new approaches and overall progress toward polio eradication in Nigeria during 2005-2006.