Caroline L Trotter1, Clément Lingani2, Katya Fernandez3, Laura V Cooper4, André Bita2, Carol Tevi-Benissan5, Olivier Ronveaux3, Marie-Pierre Préziosi6, James M Stuart7. 1. Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Cambridge, UK. Electronic address: clt56@cam.ac.uk. 2. Inter-country Support Team for West Africa, World Health Organization, Ouagadougou, Burkina Faso. 3. Department of Pandemic and Epidemic Diseases, World Health Organization, Geneva, Switzerland. 4. Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Cambridge, UK. 5. Immunization and Vaccine Development Unit, Regional Office for Africa, World Health Organization, Brazzaville, Congo. 6. Department of Immunization, Vaccines and Biologicals, World Health Organization, Geneva, Switzerland. 7. Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
Abstract
BACKGROUND: In preparation for the introduction of MenAfriVac, a meningococcal group A conjugate vaccine developed for the African meningitis belt, an enhanced meningitis surveillance network was established. We analysed surveillance data on suspected and confirmed cases of meningitis to quantify vaccine impact. METHODS: We compiled and analysed surveillance data for nine countries in the meningitis belt (Benin, Burkina Faso, Chad, Côte d'Ivoire, Ghana, Mali, Niger, Nigeria, and Togo) collected and curated by the WHO Inter-country Support Team between 2005 and 2015. The incidence rate ratios (IRRs) of suspected and confirmed cases in vaccinated and unvaccinated populations were estimated with negative binomial regression models. The relative risk of districts reaching the epidemic threshold of ten per 100 000 per week was estimated according to district vaccination status. FINDINGS: The incidence of suspected meningitis cases declined by 57% (95% CI 55-59) in vaccinated compared with unvaccinated populations, with some heterogeneity observed by country. We observed a similar 59% decline in the risk of a district reaching the epidemic threshold. In fully vaccinated populations, the incidence of confirmed group A disease was reduced by more than 99%. The IRR for non-A serogroups was higher after completion of MenAfriVac campaigns (IRR 2·76, 95% CI 1·21-6·30). INTERPRETATION: MenAfriVac introduction has led to substantial reductions in the incidence of suspected meningitis and epidemic risk, and a substantial effect on confirmed group A meningococcal meningitis. It is important to continue strengthening surveillance to monitor vaccine performance and remain vigilant against threats from other meningococcal serogroups and other pathogens. FUNDING: World Health Organization.
BACKGROUND: In preparation for the introduction of MenAfriVac, a meningococcal group A conjugate vaccine developed for the African meningitis belt, an enhanced meningitis surveillance network was established. We analysed surveillance data on suspected and confirmed cases of meningitis to quantify vaccine impact. METHODS: We compiled and analysed surveillance data for nine countries in the meningitis belt (Benin, Burkina Faso, Chad, Côte d'Ivoire, Ghana, Mali, Niger, Nigeria, and Togo) collected and curated by the WHO Inter-country Support Team between 2005 and 2015. The incidence rate ratios (IRRs) of suspected and confirmed cases in vaccinated and unvaccinated populations were estimated with negative binomial regression models. The relative risk of districts reaching the epidemic threshold of ten per 100 000 per week was estimated according to district vaccination status. FINDINGS: The incidence of suspected meningitis cases declined by 57% (95% CI 55-59) in vaccinated compared with unvaccinated populations, with some heterogeneity observed by country. We observed a similar 59% decline in the risk of a district reaching the epidemic threshold. In fully vaccinated populations, the incidence of confirmed group A disease was reduced by more than 99%. The IRR for non-A serogroups was higher after completion of MenAfriVac campaigns (IRR 2·76, 95% CI 1·21-6·30). INTERPRETATION: MenAfriVac introduction has led to substantial reductions in the incidence of suspected meningitis and epidemic risk, and a substantial effect on confirmed group A meningococcal meningitis. It is important to continue strengthening surveillance to monitor vaccine performance and remain vigilant against threats from other meningococcal serogroups and other pathogens. FUNDING: World Health Organization.
Authors: Sarah A Mbaeyi; Catherine H Bozio; Jonathan Duffy; Lorry G Rubin; Susan Hariri; David S Stephens; Jessica R MacNeil Journal: MMWR Recomm Rep Date: 2020-09-25
Authors: S M Niaz Arifin; Christoph Zimmer; Caroline Trotter; Anaïs Colombini; Fati Sidikou; F Marc LaForce; Ted Cohen; Reza Yaesoubi Journal: Med Decis Making Date: 2019-07-03 Impact factor: 2.583