Carrot or stick? The impact of reinforcement and government trust on persuading vaccine-hesitant parents during the pandemic

This study examined the effectiveness of different vaccination promotional strategies among parents of unvaccinated children aged 12–17 years during the COVID-19 pandemic. Using a 2 (reinforcement: positive vs. negative) × 2 (trust in government: high vs. low) between-subjects experimental design with 286 participants, we investigated how reinforcement strategies interact with government trust to influence parental attitudes and intentions toward child vaccination. Results revealed no significant main effect of reinforcement type on vaccination attitudes or intentions. However, trust in government emerged as a powerful predictor of both outcomes, with high-trust parents demonstrating substantially more positive attitudes and stronger intentions to vaccinate their children compared to low-trust parents. Importantly, significant interaction effects were observed—parents with low government trust responded more favorably to positive reinforcement (incentives) than negative reinforcement (restrictions), while parents with high government trust showed similar responses to both approaches. These findings highlight the critical role of trust in vaccine communication and suggest that tailored reinforcement strategies based on pre-existing trust levels may improve communication effectiveness. As declining vaccination rates for routine childhood immunizations create new public health vulnerabilities, these insights offer practical guidance for developing targeted vaccination campaigns that can effectively reach diverse populations, particularly those most resistant to standard public health messaging.