Prevalence and determinants of vaccine hesitancy in the City of Buenos Aires, Argentina: A probabilistic household survey.
BACKGROUND Vaccine hesitancy represents a growing challenge for immunization programs worldwide. In Latin America, population-based estimates derived from probabilistic surveys remain scarce, limiting the design of evidence-informed interventions. METHODS We conducted a population-based study in the City of Buenos Aires, Argentina, between April and June 2025 using a stratified multistage probabilistic sampling design embedded within an official periodic household survey. A culturally adapted version of the Vaccine Hesitancy Scale was administered and psychometrically evaluated. Household-level vaccine hesitancy was assessed using two complementary outcomes: strict hesitancy, defined as explicit refusal of recommended vaccines, and extended hesitancy, defined as a broader programmatic outcome combining refusal and reported vaccination delays related to access, convenience, or organizational barriers. Analyses accounted for sampling weights, strata, and primary sampling units. RESULTS A total of 1934 households were surveyed. The weighted prevalence of strict vaccine hesitancy was 7.1% (95% CI: 5.8-8.6).Female respondent sex (adjusted OR 2.77; 95% CI: 1.68-4.57) and lower vaccine confidence (adjusted OR 4.19; 95% CI: 2.65-6.64) were independent associated with strict vaccine hesitancy. The weighted prevalence of extended vaccine hesitancy was 24.1% (95% CI: 21.8-26.5). Lower vaccine confidence (adjusted OR 2.10; 95% CI: 1.61-2.74), female respondent sex (adjusted OR 1.33; 95% CI: 1.03-1.74), younger age, and residence in informal settlements (adjusted OR 2.00; 95% CI: 1.30-3.08) were independently associated with extended hesitancy. CONCLUSIONS Outright vaccine refusal was uncommon, but broader forms of hesitancy linked to delays and access barriers affected a substantial proportion of households. Vaccine confidence was the most consistent correlate across definitions.