Progress toward polio eradication — Worldwide, 2015–2016

In 1988, the World Health Assembly resolved to eradicate poliomyelitis. Wild poliovirus (WPV) transmission persists in only two countries (Afghanistan and Pakistan) after the removal of Nigeria from the list of countries with endemic polio in September 2015.* Indigenous WPV type 2 has not been detected since 1999 and was declared eradicated by the Global Commission for the Certification of Poliomyelitis Eradication in September 2015.† Since November 2012, when the last case of WPV type 3 was detected in Nigeria, WPV type 1 has been the sole circulating type of WPV (1). This report summarizes global progress toward polio eradication during 2015–2016 and updates previous reports (2). In 2015, 74 WPV cases were reported in two countries (Afghanistan and Pakistan), a decrease of 79% from the 359 WPV cases reported in 2014 in nine countries; 12 WPV cases have been reported in 2016 (to date), compared with 23 during the same period in 2015 (3). Paralytic polio caused by circulating vaccine-derived poliovirus (cVDPV) remains a risk in areas with low oral poliovirus vaccine (OPV) coverage. Seven countries, including Pakistan, reported 32 cVDPV cases in 2015 (4). In four of these countries, ≥6 months have passed since the most recent case or isolate. One country (Laos) with VDPV transmission in 2015 has reported three additional cVDPV cases in 2016 to date. Encouraging progress toward polio eradication has been made over the last year; however, interruption of WPV transmission will require focus on reaching and vaccinating every missed child through high quality supplementary immunization activities (SIAs) and cross-border coordination between Afghanistan and Pakistan (5,6).