Factors associated with the use of COVID-19 vaccine during pregnancy: evidence from a multicenter Brazilian cross-sectional study

OBJECTIVES: We aimed to understand factors that influence the decision-making process of Brazilian pregnant women to receive a COVID-19 vaccine during pregnancy. METHODS: We conducted a cross-sectional survey between August and December 2023 in two Brazilian cities. Pregnant women aged ≥18 years or emancipated attending antenatal care at public facilities were invited to participate. Those eligible completed a structured questionnaire developed and validated by Johns Hopkins University, covering sociodemographic characteristics, COVID-19 vaccination history, attitudes, beliefs, and reasons for vaccine acceptance or refusal. Participants were grouped as vaccinated during any pregnancy or missed vaccination during any pregnancy. Data were analyzed using descriptive statistics, chi-square tests, and t-tests (p < 0.05). Ethical approval was obtained, and data were securely managed in REDCap with quality control procedures to ensure accuracy and consistency. RESULTS: Among 402 pregnant women surveyed, 109 received a COVID-19 vaccine dose during pregnancy, while 279 missed vaccination during pregnancy. Number of doses varied by group; women vaccinated during pregnancy were more likely to have higher number of doses. There were similar overall dose counts across pregnancy trimesters. Women vaccinated during pregnancy reported greater confidence in vaccine safety and effectiveness for themselves and their fetus and were less likely to express negative beliefs about vaccination. Missing vaccination during pregnancy was associated with preference for natural immunity and concerns about vaccine unnaturalness. CONCLUSION: A low proportion of pregnant women received COVID-19 vaccines during pregnancy. Having doubts about vaccine safety, efficacy, and COVID-19 severity were associated with missing vaccination during pregnancy. Addressing these factors is crucial for enhancing public health policies and improving the adherence of pregnant women to vaccination.