Sensitivity of Acute Flaccid Paralysis Surveillance in Nigeria (2006-2015)

Background: Nigeria has made tremendous progress towards polio eradication. The country was removed from the list of polio endemic countries by the World Health Organization (WHO) in September 2015. The last cases of wild poliovirus (WPV) and circulating vaccine derived poliovirus (cVDPV) from acute flaccid paralysis (AFP) cases had onset of paralysis in July 2014 and May 2015 respectively. The country has completed the phase I of laboratory containment of poliovirus activities, has achieved and maintained certification standard surveillance and is now in the process of ensuring adequate documentation preparatory to certification in 2017. Methods: We conducted a retrospective review of AFP surveillance performance in Nigeria between 2006 and 2015 from the AFP database at the WHO Country Office. We also reviewed rapid surveillance assessment reports conducted in various states of the country within the reporting period to identify surveillance strengths and gaps as well as recommendations put forward to improve polio surveillance performance. Results: The sensitivity of AFP surveillance in Nigeria increased consistently over the past 10 years. The number of confirmed and polio compatible cases has reduced significantly during the reporting period. AFP reporting sites have been prioritized for active surveillance and community informants have been engaged and cut across several key stakeholders in community health care delivery system. Conclusion: The AFP surveillance performance in Nigeria during the reporting period demonstrated high level of sensitivity that can be relied upon to timely detect polio outbreak. Residual surveillance gaps at sub national levels however exist and must be closed to be able to identify remaining areas of poliovirus transmission should such exist as well as promptly detect possible cases of importation. Quality surveillance is also required for certification.