By Ethan Covey
The eradication of polio in Nigeria continues, with immunization campaigns reaching deeply into insurgent strongholds, according to a CDC study.
The number of children living in insurgent-held areas in Borno who have not had access to poliovirus vaccines was reduced by 87% between December 2016 and May 2017 (MMWR Morb Mortal Wkly Rep 2019;68[29]:642-646).
“Since the last detected wild poliovirus [WPV] case in 2016, the Nigerian government has made major improvements to implement additional supplementary immunization campaigns, strengthen routine immunization, improve surveillance networks and implement innovative strategies to reach more children with polio vaccines in insurgent-held areas,” said Steven Wassilak, MD, a medical epidemiologist, the CDC’s Global Immunization Division.
The number of WPV cases in Nigeria decreased from 1,122 in 2006 to six WPV type 1 (WPV1) in 2014. No WPV cases were detected during August 2014 to July 2016; and four cases were reported to Borno State from August to September 2016.
“Trained community members living in insurgent-held areas have reported suspected polio cases with no WPV identified on virologic testing, which suggests that WPV transmission might have been interrupted in Nigeria,” Dr. Wassilak added. “However, outbreaks caused by type 2 circulating vaccine–derived poliovirus (cVDPV2) are spreading internationally.”
The CDC team hoped that continued efforts in immunization and surveillance in northeastern Nigeria and neighboring countries will allow the African Regional Certification Commission to be able to conclude by 2020 that WPV transmission has been interrupted in the World Health Organization African Region.
“Improved mass polio immunization campaign quality is required to achieve interruption of all cVDPV2 transmission in Nigeria,” Dr. Wassilak said. “Further work is required to reach every child with vaccines including in inaccessible areas, ensure high-quality mass polio immunization campaign, and continue to improve on surveillance.”
