Temporal trend of vaccination coverage in children under five in Brazil

Introduction: Vaccination coverage is an important indicator of the population's protection against vaccine-preventable diseases; however, oscillations have been observed in several countries, and the World Health Organization warns of the existence of 25 million children with an incomplete vaccination schedule, with a significant portion of them in Brazil. Objective: This study aims to analyze the trends in the time series of vaccination coverage between 1998 and 2024 for the immunizers that make up the National Child Vaccination Calendar. Methods: Data were obtained from the information system of the Brazilian immunization program, and trend analyses were performed via simple linear regression. Results: Five vaccines were associated with a decreasing immunization trend, one of which was statistically significant, two with an increasing trend, one with a statistically significant trend and four with a stationary trend. Conclusion: The numbers found are alarming, considering that 41.6% of the vaccines studied show a decreasing trend and that although 1/3 of the vaccines show a stationary trend, they remained below the Ministry of Health target throughout the study period.