Field challenges to measles elimination in the Democratic Republic of the Congo

• Published in: Vaccine 2020-03, Vol.38 (13), p.2800-2807
• Main Authors: Coulborn, R.M., Nackers, F., Bachy, C., Porten, K., Vochten, H., Ndele, E., Van Herp, M., Bibala-Faray, E., Cohuet, S., Panunzi, I.
• Format: Article
• Language: English
• Subjects: Adolescent; Age; Child; Child, Preschool; Children; Cross-Sectional Studies; Democratic Republic of the Congo; Democratic Republic of the Congo - epidemiology; Documentation; Epidemics; Health facilities; Households; Houses; Humans; Immunization; Immunization Programs; Infant; Mass vaccination; Measles; Measles - epidemiology; Measles - prevention & control; Measles vaccination; Measles Vaccine - administration & dosage; Polls & surveys; Public health; Retrospective Studies; Rural areas; Sample size; Urban areas; Vaccination; Vaccination coverage; Vaccination Coverage - statistics & numerical data; Vaccine effectiveness; Vaccines
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2020.02.029

During a measles epidemic, the Ministry of Public Health (MOH) of the Democratic Republic of the Congo conducted supplementary immunization activities (2016-SIA) from August 28-September 3, 2016 throughout Maniema Province. From October 29-November 4, 2016, Médecins Sans Frontières and the MOH conducted a reactive measles vaccination campaign (2016-RVC) targeting children six months to 14 years old in seven health areas with heavy ongoing transmission despite inclusion in the 2016-SIA, and a post-vaccination survey. We report the measles vaccine coverage (VC) and effectiveness (VE) of the 2016-SIA and VC of the 2016-RVC. A cross-sectional VC cluster survey stratified by semi-urban/rural health area and age was conducted. A retrospective cohort analysis of measles reported by the parent/guardian allowed calculation of the cumulative measles incidence according to vaccination status after the 2016-SIA for an estimation of crude and adjusted VE. In November 2016, 1145 children (6–59 months old) in the semi-urban and 1158 in the rural areas were surveyed. Post-2016-SIA VC (documentation/declaration) was 81.6% (95%CI: 76.5–85.7) in the semi-urban and 91.0% (95%CI: 84.9–94.7) in the rural areas. The reported measles incidence in October among children less than 5 years old was 5.0% for 2016-SIA-vaccinated and 11.2% for 2016-SIA-non-vaccinated in the semi-urban area, and 0.7% for 2016-SIA-vaccinated and 4.0% for 2016-SIA-non-vaccinated in the rural area. Post-2016-SIA VE (adjusted for age, sex) was 53.9% (95%CI: 2.9–78.8) in the semi-urban and 78.7% (95%CI: 0–97.1) in the rural areas. Post 2016-RVC VC (documentation/declaration) was 99.1% (95%CI: 98.2–99.6) in the semi-urban and 98.8% (95%CI: 96.5–99.6) in the rural areas. Although our VE estimates could be underestimated due to misclassification of measles status, the VC and VE point estimates of the 2016-SIA in the semi-urban area appear suboptimal, and in combination, could not limit the epidemic. Further research is needed on vaccination strategies adapted to urban contexts.