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

Research Question The development of effective vaccines against COVID-19 are paramount for containing the pandemic and preventing deaths. However, even though several successful vaccines were approved worldwide, available doses are insufficient to meet current demand. How this vaccine scarcity affects individuals' willingness to be vaccinated? This paper aims to address this important public policy question, as vaccine hesitancy can hinder controlling the pandemic. In addition, what key variables moderate the relationship between vaccine scarcity and intentions to be vaccinated? Method and Data In two pre-registered experimental studies (total N = 927), we manipulated whether COVID-19 vaccines were scarce or widely available, and tested the effect of scarcity frame on one's vaccination intention. Using moderated mediation models, we also explored the role of trust in doctors and compassion for others. Study 1 was conducted with a student population, while study 2 sampled participants with or without pre-existing conditions that can make one more vulnerable to COVID-19. Summary of Findings We find that scarcity of COVID-19 vaccines decreases willingness to be vaccinated (contrary to most scarcity research findings) due to lower perceived priority to receive the vaccine. Perceived scarcity in vaccine supplies reduced average intentions to vaccinate by up to10 points on a 100-point scale. Trust in doctors decreased the deleterious effect of low perceived priority due to vaccine scarcity on vaccination intentions. For participants with high compassion, namely a greater ability to understand or be aware of the suffering of others and the need to act to end that suffering, (top 48.4% of the distribution), scarcity reduced their vaccine intentions, while for participants with low compassion scores (bottom 1.4% of the distribution), scarcity increased their vaccine intentions. Statement of Key Contributions Results from two studies indicate that public health authorities should deemphasize COVID-19 vaccine supply scarcity to improve public acceptance of the COVID-19 vaccine. Trust in doctors may be an important lever for improving COVID-19 vaccination acceptance when supplies are scarce. Public health messaging should also target highly compassionate individuals to emphasize how accepting a COVID-19 vaccine when available helps other people, even when vaccines are scarce. [ABSTRACT FROM AUTHOR]