Hesitancy Towards a COVID-19 Vaccine and Prospects for Herd Immunity

The scientific community has come together in an unprecedented effort to find a COVID-19 vaccine. However, the success of any vaccine depends on the share of the population that gets vaccinated. We design a survey experiment in which a nationally representative sample of 3,133 adults in the U.S. state their intentions to vaccinate themselves and their children for COVID-19. In the experiment, we account for uncertainty about the severity and infectiousness of COVID-19, as well as inconsistencies in risk communication from government authorities, by varying these factors across treatments. We find that 20% of people in the U.S. would decline the vaccine. General vaccine hesitancy (including not having had a flu shot in the last two years), distrust of vaccine safety, and vaccine novelty are among the most important deterrents to vaccination. Further, our results suggest that inconsistent risk messages from public health experts and elected officials reduce vaccine uptake. We use our survey results in an epidemiological model to explore conditions under which a vaccine could achieve herd immunity. We find that in a middle-of-the-road scenario with central estimates of model parameters, a vaccine will benefit public health by saving many lives but nevertheless may fail to achieve herd immunity.