The decline in childhood vaccination coverage has become a striking phenomenon in recent years in Brazil. This scenario has favored the reintroduction and increased circulation of vaccine-preventable diseases with major public health impact, such as measles. In this context, the objective of this study was to analyze the relationship between MMR vaccination coverage and measles-related hospitalization rates in Brazilian children aged 1 to <5 years, from 2013 to 2024. Observational study with ecological time-series design, using secondary data from the Departamento de Informação e Informática do Sistema Único de Saúde (DATASUS). Annual MMR vaccination coverage and measles-related hospitalizations in children aged 1 to <5 years were analyzed, both in absolute numbers and in rates per 100,000 inhabitants in this age group. To estimate the possible cumulative impact of immunization, each year’s measles hospitalization rate (t) was related to the mean MMR coverage from years t to t–4. The association between variables was assessed using Pearson’s correlation coefficient, with statistical significance set at p < 0.05. Between 2013 and 2024, MMR coverage ranged from 112.80% (2014) to 74.94% (2021), with increased measles hospitalizations between 2018 and 2020. Pearson’s correlation analysis between the mean five-year coverage (t to t–4) and the measles hospitalization rate in the current year yielded r = -0.08; p = 0.805, indicating a very weak and statistically non-significant negative correlation between the variables. In the period analyzed, no statistically significant correlation was identified between mean MMR coverage and measles-related hospitalization rates in children aged 1 to <5 years in Brazil. However, these findings do not invalidate the effectiveness of the vaccine, as factors such as localized outbreaks, regional inequality in coverage and migratory movements may have influenced the results observed.
Karoline Eliseu Favarin (Sun,) studied this question.