COVID-19 vaccination schedule, associated factors, and reasons for refusal in adults and the elderly: a population-based cross-sectional study, Rio Grande, Brazil, 2023

Abstract Objective: To estimate the prevalence of COVID-19 vaccination schedule completion and to investigate associated factors and reasons for refusal among adults and elderly residents of Rio Grande, Rio Grande do Sul state, Brazil. Methods: This was a cross-sectional study with participants from the Adult and Elderly post-COVID-19 Infection Health Indicator Follow-up, conducted in 2022-2023. The outcome was the COVID-19 vaccination schedule. Having had at least three doses of the vaccine was considered to be complete vaccination. The exposure variables were sociodemographic and morbidity characteristics. Reasons for not completing the vaccination schedule were also investigated. Prevalence rates and unadjusted and adjusted prevalence ratios were calculated. Results: Of the 1,925 respondents, 83.3% received all three doses of the vaccine. Vaccination prevalence was higher among women (85.5%), older adults (92.6%), respondents who had never smoked (83.3%) or were former smokers (87.6%), those with multimorbidity (88.6%), and those who had been informed about the importance of the vaccine (85.1%). Among those who did not complete the vaccination schedule, 15.8% did not do so because they had a reaction to the vaccine; the vaccine was not available for 8.5% when they went to get vaccinated and they did not return; 8.1% knew someone who had a reaction and were apprehensive; and 7.3% stated they had already had COVID-19. Conclusion: In all, 83.3% completed the vaccination schedule of at least three COVID-19 vaccine doses. Adherence to vaccination should be encouraged, especially in groups with lower coverage rates, such as men, younger people, and those without comorbidities.