Abstract
The COVID-19 pandemic prompted strict measures and rapid vaccine deployment in Benin and Senegal. This longitudinal study uses Generalized Estimating Equations (GEE) to analyze the evolution of vaccination intent and its determinants, focusing on attitudes, risk perceptions, and social influence. This descriptive and analytical longitudinal study included 546 Beninese and 319 Senegalese individuals aged 18 and above, selected using marginal quotas. Data were collected via Random Digit Dialing (RDD) based on a questionnaire informed by the Theory of Planned Behavior (TPB) and the Health Belief Model (HBM). Influential factors were assessed using GEE models. Vaccination intent increased more significantly in Senegal (+12.5 points, p = .000) than in Benin (+5.0 points, p = .089). There was a statistically significant increase in vaccine intent among women (+19.9 points) and individuals under 25 (+15.6 points) in Senegal, whereas in Benin, younger respondents showed a decrease (-11.5 points). In both countries, individuals surveyed in the second phase were significantly more likely to express vaccination intent (Benin: OR = 6.9; Senegal: OR = 5.0). Common positive determinants included perceived benefits, social influence, and favorable attitudes toward vaccination. Differences emerged: perceived efficacy and behavioral control were significant in Benin, while safety concerns were a major barrier in Senegal. This study highlights common and context-specific determinants of vaccination intent in Benin and Senegal. It emphasizes the need for tailored communication strategies and efforts to strengthen public trust to enhance vaccine uptake across West Africa.