Introduction: In November 2015 a measles outbreak was detected in several clustered settlements during the Northern Measles Supplementary Immunization Activities (SIAs) campaign in Gwagwalada, Nigeria, a measles outbreak was detected. Six weeks later another outbreak with 17 cases was reported in a different settlement in the same area council in December 2015 and January 2016. An outbreak investigation was initiated to characterize the outbreak in terms of time and person and implement prevention and control measures.
Methods: Suspected cases were defined as any person in Gwagwalada with onset of fever and rash between 1st November 2015 and 12th January 2016. Probable cases were defined as suspected cases with 3 days of rash or known exposure to someone with laboratory-confirmed measles. Confirmed case patients were defined as suspected or probable cases with Koplik spots or positive titer for immunoglobulin (Ig) M antibody. We conducted house to house case search, contact tracing and reviewed hospital records at the health facilities to determine the socio-demographic characteristics, clinical presentation and vaccination status of the cases.
Results: Active case search between November 2015 and January 2016 as well as record review from January 2015 to January 2016 showed that there were 109 suspected and 10 confirmed case patients. We identified 66 cases during the first reported outbreak with a case fatality rate of 6% (4 deaths) while 17 cases were identified 6 weeks later. The epidemic curve indicated a person-to-person transmission.
Conclusion: There had been cases of measles from January 2015 to November 2015 prior to the reported measles outbreak. However there was an unusual increase in the number of measles cases during the measles SIAs in communities where children were missed. Vaccination of all eligible children in the affected wards was carried out. The area council authorities and primary healthcare team need to create awareness on the importance of measles vaccination and ensure that these communities are targeted and covered during subsequent SIAs.
Keywords: Immunization; Nigeria; hard to reach; measles; outbreaks; surveillance; vaccination.