Would Monetary Incentives to COVID-19 vaccination reduce motivation?

Some people did not get the COVID-19 vaccine even though it was offered at no cost. A monetary incentive might lead people to vaccinate, although existing studies have provided different findings about this effect. We investigate how monetary incentives differ according to individual characteristics. Using panel data with online experiments, we found that (1) subsidies reduced vaccine intention but increased it after controlling heterogeneity; (2) the stronger the social image against the vaccination, the lower the monetary incentive; and (3) persistently unvaccinated people would intend to be vaccinated only if a large subsidy was provided.