Potential predictors of COVID-19 booster vaccine confidence among adult people: a cross-sectional analysis amid the Omicron surge in Southern Bangladesh.

Despite the therapeutic potential of the primary vaccine series, a lack of confidence in the COVID-19 booster vaccine poses a threat to public health and undermines its coverage at the national, regional, and global levels. This study aimed to understand COVID-19 booster vaccine confidence (CBVC) among Bangladeshi adults aged 18-49 and the potential predictors of CBVC. In line with STROBE guidelines, a face-to-face cross-sectional survey was conducted from June 15 to August 31, 2023 during the spread of the SARS-CoV-2 Omicron variant. A one-way ANOVA analysis, independent-sample t-test, and binary logistic regression were employed to assess the potential antecedents associated with CBVC. The pooled COVID-19 booster vaccine confidence was 74.3 % (95 % CI, 71.1-77.6 %) among adult polls. Majority of participants were confident that booster vaccinations are safe (64.9 %) and effective (53.8 %) against new SARS-CoV-2 variants, with 74.0 % stating that they were trusted by vaccination services. Out of the ten potential factors, "equal safety" and "trust" had a highly significant positive association with CBVC ([aOR]: 2.164 and [aOR]: 2.054, respectively). Binary analysis also revealed that "effectiveness" and "social care" had a significant positive association with CBVC ([aOR]: 1.051 and [aOR]: 1.209, respectively). In the t-test analysis, females felt more responsible for getting the booster vaccine to protect others (t = -4.21, P = 0.001), however, they also worried about unwanted side effects (t = -4.79, P = 0.001). The post-hoc comparison found that being younger and having a lower education was associated with a lower level of confidence in booster vaccines and trust. This study reported high confidence in the COVID-19 booster vaccine, but there were noticeable demographic and psychological differences in booster confidence. The provision of accurate, up-to-date information from reliable sources, as well as education about the safety and efficacy of vaccines might improve CBVC coverage among marginalized populations.