Risk factors related to the SARS-CoV-2 vaccine additional doses hesitancy among pregnant and non-pregnant people of reproductive age and partners: A Brazilian cross-sectional study.

Objective: The aim of this study was to assess the predictors of acceptance and hesitancy of additional doses of any SARS-CoV-2 (COVID-19) vaccine among pregnant or recently pregnant and non-pregnant people of reproductive age and partners in Brazil.

Methods: We conducted an online cross-sectional study from June 2022 to April 2023 and invited women and partners between 18 and 49 years old to participate. We employed a snowball strategy to reach all potential eligible participants. Our primary outcome was the acceptance rate of the COVID-19 booster vaccine. We estimated the frequency and percentage for the three groups and compared categorical variables using the Chi-square test. Moreover, bivariate, backward stepwise regression, and subgroup analyses were performed to evaluate risk factors and predictors of COVID-19 vaccine booster hesitancy. We reported the effect size as OR with a 95% CI.

Results: We included 1487 participants, and among them, 334 (22.5%) were pregnant or recently pregnant people, 905 (60.8%) were non-pregnant people, and 247 (16.6%) were male partners. Pregnant and recently pregnant people showed greater hesitancy for the COVID-19 vaccine booster than non-pregnant people (28% vs 15%, P < 0.001) and male partners (28% vs 16%, P < 0.001). Non-pregnant women accepted the COVID-19 vaccine more often than pregnant or recently pregnant people (OR 1.75; 95% CI: 1.13-2.70). The associated factors to the reduced COVID-19 vaccine booster acceptance were family income between US$ 566-945.00 (54%), evangelic religion (65%), concern about vaccine safety (80%) and perceived common vaccine importance (93%).

Conclusion: Pregnant people were more hesitant than non-pregnant people to accept the COVID-19 booster vaccine. Family income, religious beliefs, vaccine safety concerns, and perceived common vaccine importance were significant barriers to accepting COVID-19 booster vaccines. The impact of these factors was more evident among pregnant or recently pregnant people, emphasizing the harmful effect of misinformation among this vulnerable population.