Temporal trends of vaccination coverage in children under five in Brazil, 1998–2024

INTRODUCTION: Vaccination coverage is an important indicator of the population's protection against vaccine-preventable diseases, and the World Health Organization warns of the existence of 25 million children worldwide with incomplete vaccination schedules, with a significant portion of them in Brazil. OBJECTIVE: This study aims to analyze the time-series trends of vaccination coverage for 12 vaccines targeting children under five years of age in Brazil, between 1998 and 2024. METHODS: This is an ecological time-series study using official data from the information system of the Brazilian National Immunization Program. Temporal trend analyses were conducted using simple linear regression models. RESULTS: The yellow fever vaccine exhibited a statistically significant increasing temporal trend but remained below the target set by the Ministry of Health throughout the study period. In contrast, the BCG vaccine demonstrated a significant decreasing temporal trend. The trends for the other ten evaluated vaccines could not be established, as they lacked statistical significance. CONCLUSION: The results show that 11 of the 12 studied vaccines are below the Ministry of Health's target, making it evident that urgent measures must be taken to change this scenario.