Tracking progress toward polio eradication - worldwide, 2013-2014

Abstract

Global efforts to eradicate polio began in 1988 and have been successful in all but two of the six World Health Organization (WHO) regions. Within these two regions (African and Eastern Mediterranean), three countries (Afghanistan, Nigeria, and Pakistan) have never interrupted transmission of wild poliovirus (WPV). Outbreaks following importation of WPV from these countries occurred in the Horn of Africa, Central Africa, and in the Middle East during 2013-2014. The primary means of tracking polio is surveillance for cases of acute flaccid paralysis (AFP), the main symptom of polio, followed by testing of AFP patients' stool specimens for both WPV and vaccine-derived poliovirus (VDPV) in WHO-accredited laboratories within the Global Polio Laboratory Network (GPLN). This is supplemented with environmental surveillance (testing sewage for WPV and VDPV) (4). Both types of surveillance use genomic sequencing for characterization of poliovirus isolates to map poliovirus transmission and for identifying gaps in AFP surveillance by measuring genetic divergence between isolates. This report presents 2013 and 2014 poliovirus surveillance data, focusing primarily on the two WHO regions with endemic WPV transmission, and the 29 countries (African Region = 23; Eastern Mediterranean Region = six) with at least one case of WPV or circulating VDPV (cVDPV) reported during 2010-2014. In 2013, 20 of these 23 African region countries met both primary surveillance quality indicators; in 2014, the number decreased to 15. In 2013, five of the six Eastern Mediterranean Region countries met the primary indicators, and in 2014, all six did. To complete and certify polio eradication, surveillance gaps must be identified and surveillance activities, including supervision, monitoring, and specimen collection, further strengthened.

FIGURE

Combined performance indicators for the quality of acute flaccid paralysis (AFP) surveillance* in subnational areas (states and provinces) of 29 countries that were polio-affected during 2010–2014 — World Health Organization African and Eastern Mediterranean regions, 2014^† Abbreviation: NPAFP = nonpolio AFP. * The Global Polio Eradication Initiative has set the following targets for countries with current or recent wild poliovirus transmission and their states/provinces: 1) NPAFP detection rate of ≥2 cases per 100,000 persons aged <15 years, and 2) adequate stool specimen collection from ≥80% of AFP cases, with specimen adequacy defined as two specimens collected ≥24 hours apart, both within 14 days of paralysis onset, shipped on ice or frozen packs, and arriving in good condition at a World Health Organization–accredited laboratory. ^† Data are for AFP cases with onset during 2014, reported as of March 27, 2015. ^§ Per 100,000 persons aged <15 years.