Vaccination preferences and predictors of vaccine hesitancy in Brazil: a discrete choice experiment

Objective This study investigates the extent to which individual characteristics and preferences towards vaccine attributes and societal restrictions influence vaccination behaviour in a representative Brazilian population. Method We conducted a discrete choice experiment (DCE) involving 3,001 Brazilian respondents from July to September 2022 through an online panel. The DCE involved five vaccine features and two social restriction features. Participants were presented to a sequence of binary choices of hypothetical vaccination programs, with an option to opt-out. We performed multiple regression models to investigate the predictors of vaccination and opt-out decisions. We also performed a latent class logit model to estimate trade-offs between vaccination attributes and societal restrictions across groups. Results Our regression results identified that gender, religiosity, income, political orientation and trust in public health institutions were important predictors of vaccination decisions in Brazil. Our latent class models indicated significant heterogeneity and detected four main classes: (i) left-leaning, pro restrictions, who showed strong preferences for vaccine features such as its effectiveness (62.4%); (ii) left-leaning, pro mandates, who showed strong support for societal restrictions (19.5%); (iii) centrists, pragmatics, who were opposed to restrictions but supportive of vaccine features (11.4%); (iv) right-leaning, vaccine refusers, who showed a willingness to opt-out from vaccination programmes and did not show any preferences for vaccine features (6.7%). Conclusions Our findings suggest that the Brazilian population had overall high willingness to accept vaccines and displayed high trust in public health authorities. Nonetheless, the presence of a non-negligible proportion of cautious and hesitant groups may prevent the effectiveness of vaccination campaigns in the future. Lay summary This study investigated the factors that influence people’s decisions to get vaccinated in Brazil. We asked 3,001 participants to choose between different vaccination programs with various features, including vaccine effectiveness and the presence of social restrictions. We found that factors such as gender, income, religion, political views, and trust in public health institutions affected people’s vaccination decisions. The study also identified four groups: one strongly supports vaccines and their characteristics, one supports both vaccines and social restrictions, another prefers vaccines but dislikes restrictions, and a fourth is more hesitant-refuser about vaccines and more likely to opt out of vaccination. Overall, most Brazilians showed high trust in vaccines and public health advice. However, a small but significant group remains hesitant and refusing, which could pose challenges for future vaccination efforts and public health policies. Understanding these groups can help design better strategies to improve vaccination rates and protect public health.