Full vaccination coverage with valid doses among the 2017 and 2018 live birth cohort in the Southeast region of Brazil

To analyze factors associated with full vaccination coverage with valid doses, in children from four state capitals and three other cities in Southeast Brazil. Analysis of a population survey conducted in 2020-2021, with a sample stratified according to socioeconomic levels of children born in 2017-2018, with data collected through photographic records of their vaccination cards. Odds ratios (OR) and 95% confidence intervals (95%CI) for full vaccination coverage were estimated based on the characteristics of the family, mother and child. Among 8703 children, lowest coverage occurred in strata A and B (OR=0.39; 95%CI 0.23;0.67 and OR=0.38; 95%CI 0.25;0.58); in consumption level A/B (OR=0.38; 95CI% 0.28;0.52); among those with income >BRL8000/month (OR=0.23; 95%CI 0.12;0.42); in children of mothers with higher education (OR=0.47; 95%CI 0.32;0.71); in children not vaccinated exclusively in the public service (OR=0.37; 95%CI 0.26;0.51) and in children with a vaccination delay of up to 6 months (OR=0.28; 95%CI 0.22;0.37). Coverage did not reach the targets for controlling vaccine-preventable diseases and was negatively associated with higher socioeconomic status. Vaccination coverage for the full schedule with valid doses was very low, putting the control of vaccine-preventable diseases at risk in the four state capitals and three other cities in the interior region of Southeast Brazil. Brazilian National Health System managers and workers need to know the factors associated with low vaccination coverage and increased risk of abandoning the schedule, access problems and National Immunization Program difficulties. Understanding determinants of low vaccination coverage provides support for the discussion and design of effective public policies to address barriers and qualify health services for vaccination.