Poliomyelitis is an acute infectious disease caused by poliovirus, an RNA enterovirus of the species Enterovirus C, with three serotypes (1, 2, and 3). It is highly contagious and can cause acute flaccid paralysis in about 1 in every 200 to 2,000 infections, and in up to two-thirds of these cases, post-polio syndrome. In Brazil, it has been eradicated since 1989. However, falling vaccination coverage has increased the risk of reintroduction, leading the PAHO to classify the country as high risk. Coverage, which reached critical levels in 2021, has been recovering but remains below the WHO target of 95%. To evaluate poliomyelitis vaccination coverage in cities of Bahia. Ecological and exploratory study on vaccination coverage (VC) in the 417 municipalities of Bahia between 2019 and 2023. VC data were obtained from DATASUS, and the digital map from IBGE. Coverage was classified as low (<90%), medium (≥90% and <95%), and ideal (≥95%). Spatial analysis used Global Moran’s I (IM), with 199 permutations and 5% significance, to assess spatial autocorrelation, and Local Moran’s I (LISA) to identify spatial clusters. Correlation between VC and socioeconomic indicators (GDP, per capita income), demographic and perinatal variables gestational age <36 weeks, maternal age (20–34 years), schooling <8 years, and birth weight <2500 g was also investigated using Bivariate Moran’s I (IMB). TerraView and GeoDa software were used for spatial analysis. Mean VC between 2019 and 2023 was 72.9%. In all five years, coverage remained below the 95% target, with the worst rates in 2020 (70.9%) and 2021 (63.1%). Low coverage was observed in 213 municipalities, especially in the southwestern region of Bahia, notably the Brumado and Jequié areas. IMB showed statistically significant correlations between VC and maternal age, maternal schooling, gestational age, birth weight, and per capita income. Thematic maps and BoxMaps allowed identification of clusters in some regions with low VC and adverse socioeconomic variables such as low per capita income, and demographic variables such as low birth weight and prematurity. The study identified clusters of low vaccination coverage and their associated variables, providing public health managers with evidence to identify areas in need of targeted interventions.
Rosolen et al. (2026) studied this question.