A Retrospective Analysis of National Surveillance Data on the Epidemiology of Meningitis in Niger (2005 – 2020)

Background: Bacterial meningitis is a major public health problem, especially in low-income countries. It is caused by Nesseria meningitidis (Nm), a Gram-negative bacterium of the family Neisseriaceae that infects humans only. In Africa, epidemics of meningitis caused by Neisseria meningitides have been a public health problem for over a century. Aim: This study analysed national surveillance data and isolates from Niger to describe the epidemiology of bacterial meningitis from 2005 to 2020. Methods: A retrospective study was conducted using nationwide case-based surveillance data of all reported meningitis cases in Niger from 2005 to 2020. A modified case definition was used to classify the cases. Data were collected and analysed using Stata 12.0. Results: Neisseria meningitidis (Nm) was recorded over the entire period from 2005 to 2020. A total of 47,953 suspected meningitis cases and 3,276 deaths (CFR=6.83%) were reported, corresponding to an incidence of 189.01 cases per 100,000 population. The male represented 55.41% (sex-ratio male: female = 1.30), and 40.52% were 5 -14 years old. A total of 29,998 cases were reported through RNL, of which 10,979 (36.60%) were confirmed, and 6,149 (56.01%) were confirmed by culture. The predominant organism identified was N. meningitidis serogroup A (33.91%). All regions reported meningitis cases, and a consistent and substantial reduction was seen in confirmed NmA cases, with no cases occurring in the country after the completion of mass campaigns. Nevertheless, other pathogen species and Nm variants, including NmX, NmC, and Streptococcus pneumoniae, have become more prevalent. Conclusion: Increased surveillance of multiple serogroups throughout is necessary, as well as consideration of vaccination with combination vaccines rather than just using a single strain, as is currently the case with NmA.