Análise temporal da incidência de meningite pneumocócica pré e pós introdução da vacina pneumocócica conjugada 10 em Minas Gerais 2006-2023

Abstract

Introduction: Pneumococcal meningitis (PM) is an infection of the meninges caused by the bacterium Streptococcus pneumoniae, presenting nonspecific clinical symptoms such as fever, severe headache, vomiting, and neck stiffness. In Brazil, in 2010, the Unified Health System introduced routine vaccination against meningitis, using the 10-valent pneumococcal conjugate vaccine (PCV10) for children under two years of age. Objective: To perform a temporal analysis of PM incidence before and after the introduction of PCV10 in Minas Gerais from 2006 to 2023. Methods: This is an ecological study with a time-series analysis of confirmed PM cases and predominant serotypes. Data were obtained from the Notifiable Diseases Information System (SINAN), the Live Birth Information System (SINASC), and the National Immunization Program Information System (SI-PNI). A Generalized Linear Model using Poisson Regression was applied. The analysis quantified variations in PM incidence rates across different periods and age groups: 2006–2009 (“reference period, prior to PCV10”); 2010–2019 (“post-PCV10 period until the COVID-19 pandemic”); and 2020–2023 (“COVID-19 pandemic period”). PCV10 vaccination coverage (VC) was also analyzed for these periods. Results: A total of 1,730 PM cases were analyzed. The average incidence rate during the period was 0.5/100,000 inhabitants. The highest rates occurred in 2006 and 2023 (0.7/100,000 inhabitants), and the lowest were in 2020 and 2021 (0.1/100,000 inhabitants). Comparing post-PCV10 incidence rates to the reference period (2006–2009), the findings showed: (i) 20.1% reduction in 2010–2019 (IRR: 0.79; 95% CI: 0.71–0.89); and (ii) 40.2% reduction in 2020–2023 (IRR: 0.59; 95% CI: 0.51–0.69). Among children ≤ 4 years old, there was an average reduction in PM incidence rates of 32.5% in 2010–2019 (IRR: 0.67; 95% CI: 0.46–0.98) and 56.1% in 2020–2023 (IRR: 0.43; 95% CI: 0.27–0.69) compared to the reference period (2006-2009). Vaccination coverage for children under 1 year old was below the target (95%) established by the National Immunization Program (PNI) for most of the period, except in 2011–2013 (98.3%; 95.5%; 98.0%), 2015–2016 (96.8%; 100.3%), and 2018 (97.8%). For the booster dose in 1-year-old children, vaccination coverage was lower, meeting the target only in 2012 (100.6%), 2013 (100.5%), and 2023 (132.8%). According to the Poisson model, during the post-vaccination period (2010–2023), there was a 2% annual increase in vaccination coverage for children under 1 year and a 10.5% annual reduction in PM case risk. However, for the booster dose, there was a 4.5% annual decline in coverage. An increase in circulating serotypes not included in PCV10, particularly serotypes 3 and 19A, was observed after 2010. Conclusion: The downward trend in PM cases demonstrates the positive impact of public health policies, particularly vaccination. The reduction in vaccination coverage among children under two years of age highlights the need to maintain immunization efforts. The increase in circulation of serotypes not covered by PCV10 calls for evaluating the potential introduction of vaccines like PCV13 into the public health system.