Vaccination coverage and factors associated with incomplete polio vaccine schedule in children born in 2017-2018, in state capitals and interior region municipalities of Northeast Brazil

ABSTRACT Objective To analyse vaccination coverage and factors associated with incomplete polio vaccination in a cohort of children born in 2017-2018, in state capitals and interior region municipalities of Northeast Brazil. Methods Household survey of children aged ≤24 months conducted between 2020 and 2022. Vaccination coverage and dropout rates were estimated, as well as factors associated with incomplete vaccination, analyzed by calculating odds ratios (OR) and 95% confidence intervals (95%CI). Results : Among 12,137 children, vaccination coverage (4 doses) was 80.9% (95%CI 78.4;83.1); 8.4% were not vaccinated. Not having a vaccination card (OR=18.06; 95%CI 10.01;32.61) and use of private services (OR=1.46; 95%CI 1.23;1.74) were associated with incomplete vaccination. Higher dropout rates were found for the booster dose, especially in the highest stratum. Conclusion Low vaccination coverage, poor dose follow-up and high dropout rates were found for polio vaccines in the areas studied.