Ongoing Outbreak of
                    <i>Neisseria meningitidis</i>
                    serogroup B in Pará State, Brazilian Amazon Region, following the COVID-19 pandemic

doi:10.1093/ofid/ofag501

DOI: 10.1093/ofid/ofag501 ISSN: 2328-8957

Ongoing Outbreak of Neisseria meningitidis serogroup B in Pará State, Brazilian Amazon Region, following the COVID-19 pandemic

Diana da Costa Lobato, Ângela Cristina dos Reis Maia de Souza, Caroline Gava, Camilla de Miranda Ribeiro, Raissa dos Santos Calado Sampaio de Alencar, Greice Madeleine Ikeda do Carmo, Rosa Márcia Saraiva Gentil, Susan Beatriz Batista de Oliveira, Carlos Henrique Camargo, Claudio Tavares Sacchi, Karoline Rodrigues Campos, Maria Eduarda de Araújo Morais, Gabriela Andrade de Carvalho, Adrianne da Silva Zifirino, Ana Paula Silva de Lemos, Danielle Melo Sardinha, Karla Valéria Batista Lima

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Abstract

Background

Invasive meningococcal disease (IMD) remains a major cause of mortality worldwide, yet its dynamics in the Brazilian Amazon are poorly understood. Following the COVID-19 pandemic, serogroup B IMD resurged in Brazil, raising concerns about changing transmission patterns in regions with limited healthcare access.

Methods

We conducted an epidemiological and genomic investigation of an ongoing IMD outbreak in Pará State, Brazilian Amazon, between 2023 and 2025. Clinical, demographic, and outcome data were integrated with whole-genome sequencing of 69 isolates. Multivariate logistic regression identified independent predictors of mortality, and phylogenomic analyses characterized transmission dynamics and clonal expansion.

Results

A total of 343 IMD cases were identified, of which 321 (93.6%) were caused by serogroup B, resulting 34 deaths (case-fatality rate, 10.6%). Incidence increased up to fivefold compared with national rates and disproportionately affected young children and adults. Mortality was independently associated with meningococcemia (adjusted OR, 84,52; 95% CI, 5.70–1253.65; p=0.001) however, this finding should be interpreted with caution due to the small number of meningococcemia cases.

Genomic analysis identified a predominant ST-7983/cc60 lineage, accounting for 64 of 69 sequenced isolates (92.7%). This lineage displayed limited genetic diversity (median, 7 SNPs), consistent with sustained regional transmission across multiple municipalities.

Conclusions

A highly clonal serogroup B meningococcal outbreak emerged in the Brazilian Amazon following the COVID-19 pandemic, with substantial mortality and rapid geographic spread. These findings highlight the importance of strengthened genomic surveillance and support targeted vaccination strategies to improve outbreak preparedness in underserved regions.