Abstract | BACKGROUND: METHODS: We obtained data for the incidence of meningitis before and after vaccination from national records between January, 2009, and June, 2012. In 2012, surveillance was enhanced in regions where vaccination with PsA-TT had been undertaken in 2011, and in one district where a reactive vaccination campaign in response to an outbreak of meningitis was undertaken. Meningococcal carriage was studied in an age-stratified sample of residents aged 1-29 years of a rural area roughly 13-15 and 2-4 months before and 4-6 months after vaccination. Meningococci obtained from cerebrospinal fluid or oropharyngeal swabs were characterised by conventional microbiological and molecular methods. FINDINGS: Roughly 1·8 million individuals aged 1-29 years received one dose of PsA-TT during a vaccination campaign in three regions of Chad in and around the capital N'Djamena during 10 days in December, 2011. The incidence of meningitis during the 2012 meningitis season in these three regions was 2·48 per 100,000 (57 cases in the 2·3 million population), whereas in regions without mass vaccination, incidence was 43·8 per 100,000 (3809 cases per 8·7 million population), a 94% difference in crude incidence (p<0·0001), and an incidence rate ratio of 0·096 (95% CI 0·046-0·198). Despite enhanced surveillance, no case of serogroup A meningococcal meningitis was reported in the three vaccinated regions. 32 serogroup A carriers were identified in 4278 age-stratified individuals (0·75%) living in a rural area near the capital 2-4 months before vaccination, whereas only one serogroup A meningococcus was isolated in 5001 people living in the same community 4-6 months after vaccination (adjusted odds ratio 0·019, 95% CI 0·002-0·138; p<0·0001). INTERPRETATION: PSA-TT was highly effective at prevention of serogroup A invasive meningococcal disease and carriage in Chad. How long this protection will persist needs to be established. FUNDING: The Bill & Melinda Gates Foundation, the Wellcome Trust, and Médecins Sans Frontères.
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Authors | D M Daugla, J P Gami, K Gamougam, N Naibei, L Mbainadji, M Narbé, J Toralta, B Kodbesse, C Ngadoua, M E Coldiron, F Fermon, A-L Page, M H Djingarey, S Hugonnet, O B Harrison, L S Rebbetts, Y Tekletsion, E R Watkins, D Hill, D A Caugant, D Chandramohan, M Hassan-King, O Manigart, M Nascimento, A Woukeu, C Trotter, J M Stuart, McJ Maiden, B M Greenwood |
Journal | Lancet (London, England)
(Lancet)
Vol. 383
Issue 9911
Pg. 40-47
(Jan 04 2014)
ISSN: 1474-547X [Electronic] England |
PMID | 24035220
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2014 Daugla et al. Open Access article distributed under the terms of CC BY. Published by Elsevier Ltd. All rights reserved. |
Chemical References |
- MenAfriVac
- Meningococcal Vaccines
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Topics |
- Adolescent
- Adult
- Age Distribution
- Carrier State
(diagnosis, epidemiology, prevention & control)
- Chad
(epidemiology)
- Child
- Child, Preschool
- Epidemics
- Humans
- Incidence
- Infant
- Meningitis, Meningococcal
(diagnosis, epidemiology, prevention & control)
- Meningococcal Vaccines
- Neisseria meningitidis, Serogroup A
(isolation & purification)
- Population Surveillance
(methods)
- Vaccination
- Young Adult
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