The Brazilian National Immunization Program has been in place for over 50 years and is highly robust. From 2000 to 2015, vaccination coverage targets were achieved; however, from 2016 onward, there was a significant decline, aggravated by the COVID-19 pandemic. In 2021, more than 400,000 children in Brazil did not receive the first dose of the DTP vaccine (DTP1), and were considered zero-dose children. This study aimed to assess DTP1 coverage in the state of São Paulo, Brazil, between 2003 and 2024, based on spatial and temporal distribution and association with municipal socioeconomic characteristics. Ecological study on the spatial and temporal distribution of DTP1 coverage in São Paulo state, using time points in 2005, 2010, 2015, 2020, 2022, and 2024. The unit of analysis was the municipality. Aggregated data on doses administered and live births in the 645 municipalities, as well as covariates (resident population, Family Health Strategy (ESF) coverage, and Gini index), were publicly available from the Department of Informatics of SUS (DATASUS) and IBGE. Analyses were conducted using SaTScan and GeoDa software. Temporal analysis showed a temporal cluster of low coverage throughout the state beginning in 2019 for DTP1. Local Moran’s I (LISA) consistently indicated positive spatial autocorrelation over the 2005–2024 period for rates smoothed by the local Bayesian method, revealing persistent territorial clusters of similar vaccination coverage. The same index showed no spatial autocorrelation in 2005 and 2010 for crude rates, indicating homogeneity in a context of high coverage. In general, positive spatial autocorrelation was observed between vaccination coverage and ESF coverage, and negative autocorrelation between coverage and Gini index and resident population. The context of temporal clusters of low vaccination coverage was associated with pockets of high and low coverage, giving rise to clusters of zero-dose children for DTP1. These pockets show spatial correlations possibly influenced by sociodemographic factors. This situation suggests the need for regionalized strategies to achieve vaccination equity.
López et al. (Sun,) studied this question.