Abstract
BACKGROUND: Since the introduction of the A conjugate vaccine (MenAfriVac) in 2010, epidemics of Neisseria meningitidis serogroup A have declined sharply in Africa, giving rise to other serogroups and pathogens, including Streptococcus pneumoniae and Haemophilus influenzae. In Guinea, located in the meningitis belt, post-vaccination surveillance remains essential to adapt prevention and diagnostic strategies. This study aimed to analyze the epidemiological evolution in order to assess the impact of vaccination and guide policies to combat emerging pathogens. METHODS: We conducted a retrospective descriptive cross-sectional study between January 2021 and December 2024, including all suspected cases of meningitis with compliant cerebrospinal fluid (CSF) sampling. Clinical, demographic, geographic and vaccine data were collected. The samples collected were analyzed at the national reference laboratory by triplex PCR targeting N. meningitidis, S. pneumoniae and H. influenzae. Statistical analyses were performed with R software (version 4.3.0). RESULTS: Out of 1545 suspected cases, 81 (5.24%) were confirmed positive: S. pneumoniae (80.25%) and H. influenzae (19.75%). No cases of N. meningitidis have been detected. Conakry accounted for 74.05% of notifications but with a low positivity rate (4.11%), unlike Mamou (75%) and Faranah (42.1%). Adults (18-80 years) had the highest proportion of confirmed cases (10.63%). Nearly half of the confirmed cases had an unknown vaccination status. The temporal evolution showed a surge in 2021, followed by regular low circulation, then a brief peak in February 2024. CONCLUSION: In the post-MenAfriVac context, bacterial meningitis persists in Guinea and is now dominated by Streptococcus pneumoniae. These findings highlight the need to strengthen molecular surveillance, improve vaccination data recording, and adapt prevention strategies to address emerging non-meningococcal pathogens.