The US Food and Drug Administration’s emergency authorization of three COVID-19 vaccines in a span of three months was welcome news to many who were eager to get inoculated; but for others, it spelled risk. According to polls in recent months, about a third of American adults, including some health-care workers, have reported being skeptical of the vaccines’ safety—or said they would refuse one if offered.
It’s generally accepted that health status, income, and race may influence vaccine hesitancy, but research by Vanderbilt’s Jennifer S. Trueblood, Chicago Booth’s Abigail Sussman, and Booth postdoctoral scholar Daniel O’Leary finds that aversion to financial risk may also predict vaccine hesitancy. Their study suggests that public-health messages that take risk tolerance into account could encourage vaccine take-up.
The researchers looked at data from surveys they conducted from June to December 2020, which asked respondents a range of questions, some pertaining to psychological variables, such as risk preferences, and others to attitudes and beliefs about the pandemic, such as openness to vaccines. For most of this time period, vaccines were still in the process of being tested and authorized, so efficacy and safety remained unknown. The surveys were given in waves, mostly weekly, and included more than 34,000 US participants in total.
The researchers were particularly interested in how likely respondents said they’d be to get a vaccine if it was authorized by the FDA on either a standard time frame or an expedited one. They correlated the responses with two measures of financial-risk tolerance: how regularly participants played the lottery and how likely they were to risk money in a theoretical gambling scenario.
Having a higher tolerance for financial risk was linked to an increased willingness to take a vaccine under both authorization time frames, they find. This suggests that “financial risk preferences predict vaccine take-up, illustrating the importance of thinking about vaccines in terms of risky decision making,” the researchers write.
Such thinking can be used to craft effective messaging, they suggest. In a second part of the study, the researchers had 1,000 participants, recruited on Amazon Mechanical Turk, read one of three blurbs about a theoretical vaccine’s benefits. One group read details about the vaccine’s predicted effectiveness, another about the vaccination rate needed to achieve herd immunity, and a third received both pieces of information. Then participants reported how long they’d likely wait, in months, to receive a vaccine after it was authorized.
People in the group whose message stressed only the coverage needed for herd immunity were willing to get the vaccine significantly sooner than those in either of the other groups—that is, participants responded to the social benefits of the vaccine rather than its efficacy. The researchers suggest that this messaging may be effective because it focused attention on the vaccine’s rewards—immunity for both the community and the self—which may have reduced attention to the vaccine’s perceived risks.
“While vaccines are created to minimize risk from illness, we find that individuals tend to view getting them as risky,” says Sussman. “Our findings suggest that government agencies or health-care systems could increase vaccine take-up either by effectively communicating the low risk profile of COVID-19 vaccines or by drawing attention away from these risks.”