Progress toward poliomyelitis eradication - Nigeria, January 2009-June 2010.

Nigeria has maintained a high incidence of wild poliovirus (WPV) cases attributed to persistently high proportions of under- and unimmunized children, and, for many years, the country has served as a reservoir for substantial international spread. In 2008, Nigeria reported 798 polio cases, the highest number of any country in the world. This report provides an update on poliovirus epidemiology in Nigeria during the past 18 months, January 2009-June 2010, and describes activities planned to interrupt transmission. Reported WPV cases in Nigeria decreased to 388 during 2009 (24% of global cases), and WPV incidence in Nigeria reached an all-time low during January--June 2010, with only three reported cases. Cases of circulating type 2 vaccine-derived poliovirus (cVDPV2), which first occurred in Nigeria in 2005, also declined, from 148 during the 12 months of 2009, to eight during the 6-month period, January-June 2010. One indicator of the effectiveness of immunization activities is the proportion of children with nonpolio acute flaccid paralysis (AFP) who never have received oral poliovirus vaccine (OPV). In seven high-incidence northern states of Nigeria, this proportion declined from 17.6% in 2008 to 10.7% in 2009. During 2009-2010, increased engagement of traditional, religious, and political leaders has improved community acceptance of vaccination and implementation of high-quality supplementary immunization activities (SIAs). Enhanced surveillance for polioviruses, further strengthened implementation of SIAs, and immediate immunization responses to newly identified WPV and cVDPV2 cases will be pivotal in interrupting WPV and cVDPV2 transmission in Nigeria.