Scarcity in COVID-19 vaccine supplies reduces perceived vaccination priority and increases vaccine hesitancy

In two experimental studies, we tested the effect of COVID-19 vaccine scarcity on vaccine hesitancy. Based on extensive scarcity literature, we initially predicted that high (vs. low) scarcity would increase demand for vaccines, operationalized as one's willingness to receive a vaccine. Contrary to this prediction, Study 1 showed that scarcity of vaccines reduced participants’ sense of priority which, in turn, also reduced their vaccination intentions. Trust in doctors moderated the effect of perceived vaccination priority on vaccination intentions such that for individuals with high trust in doctors, reduced perceived priority did not reduce their vaccination intentions as much. Study 2 replicated these effects with a more general population sample, which included at-risk individuals for COVID-19 complications. At-risk participants (vs. low-risk) had higher perceived vaccination priority, but describing vaccine doses as scarce reduced vaccination intentions similarly across both groups. Moreover, Study 2 demonstrated that compassion for others is a boundary condition of the effect of vaccine scarcity on vaccination intentions. For participants with high compassion, scarcity reduces willingness to receive a vaccine; for participants with low compassion, scarcity increases their willingness to be vaccinated. Our results suggest that health policymakers need to deemphasize the scarcity of vaccines to increase vaccine acceptance.