Pertussis is a droplet-transmitted disease affecting the respiratory system, caused by the bacterium Bordetella pertussis. In children under one year, the likelihood of severe forms and even hospitalization is higher. Therefore, the vaccination schedule with DTP (triple bacterial vaccine) and its booster doses is extremely important for this age group. The objective of this study is to analyze the correlation between DTP vaccination coverage and notified pertussis cases in Brazilian regions. Epidemiological, descriptive and retrospective population-based study. Data were obtained from the Sistema de Informação de Agravos de Notificação (SINAN) for the period 2015 to 2024. Sociodemographic variables were analyzed. Analysis of DTP vaccination coverage in children under one year between 2015 and 2022 revealed that the South and Southeast regions had the highest coverage in the period, 86.99% and 84.23%, respectively, while the North region had the lowest coverage (72.03%). However, in 2023 and 2024, there was a partial recovery in coverage, though still below the 95% target. Regarding pertussis cases in infants, data showed that, comparing 2023 to 2024, there was a 991.94% increase. In terms of age group, the highest number of cases was among 2- to 3-month-olds, with a peak of 1,501 cases in 2-month-old infants during the period; lethality was also highest in this group, with 29 confirmed deaths. Distribution by region showed the Southeast leading with 2,618 cases, followed by the Northeast (2,327), South (1,743), Center-West (534) and, lastly, the North (404 cases), which may be explained by its lower population density or underreporting. Although DTP coverage has improved in the last two years, data showed that regions with higher primary vaccination coverage (South and Southeast) had high pertussis notification rates in children under one year, and the year (2024) with better coverage also had the highest number of notifications. This may be associated with decreased booster vaccination and more effective diagnosis in these regions.
Couto et al. (Sun,) studied this question.