Measles Outbreak Investigation and Vaccination Coverage Assessment - Rey Bouba Health District, North Cameroon, April 2018: A Case-Control study
Measles, the fourth leading cause of death among children <5years, is a disease under surveillance in Cameroon. The country experienced multiple outbreaks from 2016 to 2017. In March 23rd , 2018, the national reference labo- ratory confirmed seven cases of measles from a village in Rey Bouba Health District (HD) in north Cameroon. The outbreak investigation which took place from 13 to 20 April 2018, aimed to identify cases, risk factors and vaccina- tion coverage.
We conducted a case-control study and a vaccination coverage assessment. A measles case was anyone living in Rey- Bouba HD with fever, generalized maculopapular rash and/or cough, cold conjunctivitis, having an epidemiological link with a case. We matched one case with one control from the same neighborhood sex and age. We reviewed consultation records in health facilities and searched cases in the community. We recorded age, sex, location and vaccination status. Vaccination coverage among all under 15years healthy children around cases was assessed through mother’s reports and/or vaccination card. We performed univariate and multivariate analysis using odds ratios with a 95% Confidence interval.
Overall, we identified 68 cases from February to April 2018. One died, case fatality rate was 1.47%. Median age was 4 years [6 months-22 years]. Female/male Sex ratio was 1.2. A nomad camp had the second highest attack rate, 3.23%. Of the 55 cases with vaccination information, 76.3% (42/55) were unvaccinated. We matched 55 cases with 55 controls.
The risk factors were: contact with cases (OR=7, 95%CI [1.3-35.3]) and bad personal hygiene (OR=6, 95%CI [1,5-22]). Overall, we enrolled 254 <15years children to assess vaccination coverage. Vaccinated children represented 41% (104/254) and among 61% (63/104) of them, vaccination card was unavailable.
Contact with a sick person and bad personal hygiene were risk factors. Low immunization coverage in the HD could explain this measles outbreak. A vaccination campaign was recommended in this HD, especially in the nomad camp and strengthening of routine immunization .