Continued Endemic Wild Poliovirus Transmission in Security-Compromised Areas — Nigeria, 2016

Weekly / February 24, 2017 / 66(7);190–193

Chimeremma Nnadi, MD, PhD1; Eunice Damisa, MPH2; Lisa Esapa, MPH1; Fiona Braka, MBBS3; Ndadilnasiya Waziri, DVM4; Anisur Siddique, MD4; Jaume Jorba, PhD5; Gatei wa; Nganda, DVM1; Chima Ohuabunwo, MD1; Omotayo Bolu, MD1; Eric Wiesen, MS1; Usman Adamu, MBBS2(View author affiliations)

View suggested citation

Summary

What is already known about this topic?

In August 2015, 1 year after the last known case of wild poliovirus (WPV) infection was reported in Nigeria in July 2014, the World Health Organization removed Nigeria from the list of endemic countries because of the high likelihood that endemic WPV circulation had been interrupted in Nigeria. However, Borno State in northeastern Nigeria has experienced years of armed insurgency, which has hampered implementation of effective polio eradication activities.

What is added by this report?

During August and September 2016, four WPV cases and one circulating vaccine-derived poliovirus (cVDPV) isolate were reported in accessible areas of Borno State. Analysis of the WPV isolates showed limited genetic relationship, indicating prolonged undetected transmission. In response, regionally synchronized supplementary immunization activities were conducted in five Lake Chad basin countries, and >30 million children in 18 northern states in Nigeria were vaccinated. Additional measures to strengthen polio surveillance quality were implemented in accessible areas of Borno State. Ongoing conflict-related insecurity continues to restrict polio workers’ access to populations in insurgent-held areas.

What are the implications for public health practice?

Although the areas that are insurgent-held have diminished over the last year, about 40% of communities in Borno State remain inaccessible. Response to the detection of WPV and cVDPV was highly successful in accessible areas. Increasing polio vaccination coverage and improving surveillance quality among cohorts of unimmunized and underimmunized populations is a critical public health need in Borno and the Lake Chad region.