Meningococcal disease in Argentine children was mainly serogroup B, surveillance finds

Researchers conducted active surveillance at six pediatric sentinel hospitals in Argentina from January 2020 through December 2024. The study included children younger than 15 years with suspected invasive meningococcal disease (IMD), confirmed by culture or polymerase chain reaction from a normally sterile site. The analysis covered 234,264 pediatric hospital discharges and used genomic methods to characterize strains and estimate theoretical 4CMenB coverage.

Twenty-seven IMD cases were confirmed, corresponding to 1.2 cases per 10,000 discharges (95% CI, 0.8–1.7). Four children died, giving a case-fatality rate of 14.8%; all were previously healthy, younger than 5 years, and had sepsis with a hospital stay of one day or less. Among 20 cases with a determined capsular group, 19 were serogroup B and one was serogroup C; no Y or W cases were identified. Estimated 4CMenB coverage was 77.3%, driven by predominance of the ST-162 clonal complex.

The findings describe residual disease after Argentina introduced MenACWY vaccination into its national program in 2017. The small number of cases and the theoretical nature of the vaccine-coverage estimate limit conclusions about vaccine impact or expected effectiveness. The authors say the findings support evaluating serogroup B vaccination as a complementary prevention strategy; they do not establish a change in vaccination policy.