Impacto da vacinação contra meningites ACWY em adolescentes no Brasil

Abstract

Introduction: Invasive meningococcal disease (IMD) is a serious acute bacterial infection caused by Neisseria meningitidis, which colonizes the human nasopharynx and is transmitted through respiratory droplets from asymptomatic or symptomatic carriers. In its invasive form, it is characterized by one or more clinical syndromes, with meningococcal meningitis being the most frequent and meningococcemia the most severe form. Meningococcemia is considered a public health priority due to its rapid onset, high mortality rate, and irreversible sequelae among survivors. Vaccination is considered the most effective way to prevent IMD, with specific serogroups used routinely for immunization and outbreak control. The MenACWY conjugate vaccine has been used in Brazil in adolescents since 2020, as they are important carriers of the etiological agent in the nasopharynx. Due to the global expansion and the serious and unpredictable nature of meningococcal disease, continuous surveillance is necessary to monitor the epidemiology of the disease in each country and region for rapid outbreak detection and monitoring of disease behavior over time. Objective: To evaluate the impact of ACWY meningitis vaccination in adolescents aged 11 to 14 years in Brazil and Brazilian regions, between 2015 and 2023. Method: This is a comparative study of the incidence of meningococcal meningitis in Brazil between the pre-vaccination (2015 to 2019) and post-vaccination (2020 to 2023) periods. Results: From 2015 to 2023, 9083 notification forms from SINAN were analyzed, obtaining 498 cases with a specific diagnosis of meningococcal disease and/or meningococcemia, with 233 serogrouped cases. Of these, 14.6% resulted in death due to meningococcal disease. The highest incidence was of serogroup C, followed by serogroup B. There was a reduction in incidence, mortality, and case fatality rates for MD in adolescents in Brazil from 2015 to 2023. Vaccination coverage in the 11-year-old age group was 32.48%. Conclusion: The study highlighted the weakness of notifications regarding meningococcal serotyping and many unfilled fields in the Notification Form. Time series analysis showed a significant decrease in IMD cases from 2018 onwards; however, it is not possible to infer that this occurred due to the introduction of vaccines for adolescents, since social isolation measures and mask use occurred during this same period due to the COVID-19 pandemic. Studies evaluating the behavior of IMD over a longer period are necessary. Although the benefits of the vaccine are known, they can be improved by increasing vaccination coverage and introducing the vaccine to children under 5 years of age, including protection against serogroup B. Future studies are recommended to assess the impact of its effects on the disease burden in the country.