Impact of MenAfriVac on Meningococcal A Meningitis in Cameroon: A Retrospective Study Using Case-by-Case-Based Surveillance Data from 2009 to 2015.

Bouba Gake,Jean-Pierre Lombart,Bouba Abdouraman,Elise Claudine Seukap,Ahmadou Aissatou,Alain G Etoundi Mballa,Nelly-Michèle Gake,Marie-Christine Fonkoua,Crescence Satou Ngah,Bonaventure Babinne Graobe,Elias Nchiwan Nukenine

doi:10.1155/2021/4314892

Abstract

Meningococcal meningitis is a public health concern in Africa. Conjugated vaccine against serogroup A Neisseria meningitidis (MenAfriVac) was used in mass vaccination and was proved to have a good impact in the meningitis belt. There is a lack of information about the impact of this intervention in Cameroon after mass vaccination was undertaken. This study aimed at filling the gap in its unknown impact in Cameroon. A retrospective longitudinal study using biological monitoring data of case-by-case-based surveillance for meningitis was obtained from the National Reference Laboratories from 1 January 2009 to 20 September 2015. Immunization coverage data were obtained from Regional Public Health Delegations where immunizations took place. We compared the risks of vaccine serogroup occurrence before and after vaccinations and calculated the global impact using Halloran's formula. Annual cases of meningitis A decreased gradually from 92 in 2011 to 34 in 2012 and then to 1 case in 2013, and since 2014, no cases have been detected. The impact was estimated at 14.48% (p=0.41) in 2012 and then at 98.63% (p < 0.0001) after the end of vaccinations in 2013. This survey confirms the effectiveness of the MenAfriVac vaccine in Cameroon as expected by the WHO. The surveillance must be pursued and enhanced to monitor coming immunizations measures with multivalent conjugated vaccines for this changing threat.

Highlights

IntroductionA central African country with 23 million inhabitants, has experienced epidemic meningococcal meningitis as other countries of the “African meningitis belt,”
Cameroon, a central African country with 23 million inhabitants, has experienced epidemic meningococcal meningitis as other countries of the “African meningitis belt,”where Neisseria meningitidis (N. m) historically caused epidemics [1, 2]
From 1 January 2009 to September 2015, a total of 3109 cerebrospinal fluids (CSFs) samples were sent to Center Pasteur of Cameroon (CPC) for biological monitoring of meningitis. 2779 CSFs were analyzed at Garoua’s laboratory (89.4%) and 330 at Yaounde’s

Summary

Introduction

A central African country with 23 million inhabitants, has experienced epidemic meningococcal meningitis as other countries of the “African meningitis belt,”. Where Neisseria meningitidis (N. m) historically caused epidemics [1, 2]. This belt extends from Senegal at the West to Ethiopia at the East, including 26 countries, with about million inhabitants exposed to the risks of epidemics [1, 2]. Cerebrospinal meningitis epidemics mainly affected four regions of Cameroon: in 1992 in the Far-North region with cases and 968 deaths. In the North region, epidemics occurred in 1993 with 1190 cases and 136 deaths; and in 1998 there were 2054 cases and 225 deaths [14]. With the evolution of the climate change, the Northwest region that was not part of this belt is currently included

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