Messages emphasizing the personal health benefits of COVID-19 vaccines have the best chance of increasing vaccination levels across the nation, according to research conducted by University of Wyoming economists.

"Our findings suggest that several forms of public messages can increase vaccination intentions, but messaging that emphasizes personal health benefits had the largest impact," says UW PhD student Madison Ashworth, lead author of a paper that appears today in the prestigious Proceedings of the National Academy of Sciences.

The new research is the latest in a series of coronavirus-related studies conducted by UW College of Business economists Ashworth, Linda Thunstrom, Todd Cherry, Stephen Newbold and David Finnoff.

The researchers were among the first to identify vaccine hesitancy as a potential stumbling block in the effort to end the COVID-19 pandemic, and vaccine hesitancy has turned out to be prevalent. Recent surveys suggest that 60-70% of U.S. adults intend to be vaccinated for COVID-19, which falls short of the threshold identified by public health experts to achieve herd immunity.

To examine the impact on vaccine intentions of a variety of public health messages, the researchers surveyed a representative sample of 3,048 adults in the United States. The economists compared three messages that described the benefits of taking the vaccine: benefits to personal health; benefits to the health of family, friends and community members; and benefits to local and national economies—as well as a fourth message that emphasized the rigor and safety protocols of the vaccine development process. They also examined the effect of combining multiple messages.

The message about private health benefits increased intended vaccinations by 16 percentage points, significantly more than the other messages.

"The strong response to the private benefit message may partly reflect the political polarization of vaccine hesitancy in the U.S.," the researchers wrote. "Conservatives are more hesitant and have a particularly individualistic worldview. They might, therefore, be particularly responsive to information that stresses private benefits. Our data offer some support for this idea: The effect of the private benefit message on vaccine intentions is larger for conservatives than for moderates or liberals."

The increase in vaccine intentions was stronger for a group that received only the private benefit message than it was for a group that received all three messages, the economists note.

"This suggests there are no benefits to communicating several different types of benefits, potentially due to information overload," they wrote.

The researchers also say the source of information also likely matters, and trusted sources may vary across subgroups. For example, previous research shows that messages promoting social distancing are more effective coming from a family physician than from a governor or private citizen.

The new study shows that people with low trust in government agencies are 14 percentage points less likely to want a vaccine, compared to those with medium trust. Of those who don't want to be vaccinated, 90% worry about the vaccine's side-effects and novelty, and 75% lack trust in vaccine developers and the Food and Drug Administration to truthfully disclose a vaccine's risks and effectiveness.

"Our vaccine safety message did little to overcome a lack of confidence in the vaccine," Ashworth says.

While their findings show that messages about the private benefits of COVID-19 vaccination are most effective, the economists suggest more research to explore the effectiveness of different information channels for promoting vaccines.