Appeals to community spirit, shame most likely to shift vaccine attitudes

Pro-vaccine messages that appeal to community spirit or evoke the sense of embarrassment people would feel if they were to spread COVID-19 to friends and family are effective in persuading individuals to get vaccinated and encourage others to do the same, according to a new Yale study.

The study, published in the journal Vaccine, incorporates two survey experiments to gauge how a broad range of messages affect people’s intentions to get vaccinated, their willingness to persuade those they care about to get the shots, and their judgments of individuals who decide against receiving the vaccine.

The first survey tested the efficacy of 11 messages appealing to varied interests, attitudes, and emotions against a control group of respondents who viewed a message unrelated to COVID-19. The researchers then retested the six best-performing messages in a nationally representative survey of American adults.

Among those six messages, three were determined to be most effective in the first survey in persuading people to get vaccinated, encourage others to do so, and negatively judge those who go unvaccinated: One appealed to people’s sense of community and the need to work together to protect everyone through vaccination; another combined the pro-community message with an evocation of the embarrassment one would feel if they got someone close to them sick after refusing the vaccine; and a third emphasized that there is nothing brave about ignoring public health advice and refusing the vaccine.

“Our work shows that messages emphasizing collective action on behalf of the community, combined with the notion of reciprocity, are effective in persuading individuals to say they will get vaccinated and encourage others to get the vaccine,” said Gregory A. Huber, the Forst Family Professor of Political Science in Yale’s Faculty of Arts and Sciences and a co-author of the study. “It also was interesting that emotional appeals, such as evoking embarrassment, motivate people to reach out to others. That second-level effect — encouraging others to get vaccinated — is likely very important to increasing the vaccination rate.”

Scholars and faculty from Yale’s School of Medicine, School of Public Health, School of Nursing, Department of Political Science, and the Institute for Global Health collaborated on the study with support from Yale’s Tobin Center for Economic Policy. By evaluating a series of messages in two successive experiments, Huber said, the study stands out from prior research that assessed the effectiveness of specific messages.

“It’s not enough to know if one message works; you want to know which messages work best,” he said. “With this study, we tested a range of messages, and then retested the ones that showed promise to see if they worked again. This is important because as the pandemic goes on, the people who avoid vaccination become increasingly difficult to persuade, so we need to know what works best and if our best messages continue to be effective.”

Participants in the first survey, fielded in July 2020, were randomly assigned to either a control group, which was presented a message on the effectiveness of bird feeders, or into groups that received one of 11 messages supporting vaccination. One of those groups read just a baseline informational message, which stated that getting vaccinated reduces the risk of contracting COVID-19 or spreading the virus to others. It also emphasized that the vaccines were safe and estimated to save millions of lives per year.

The other groups received the same baseline message along with one of 10 additional messages that took various approaches to persuasion, including: appeals to people’s self-interest or community interest; messages combining an appeal to the collective good with one of three emotions (guilt, embarrassment, or anger); statements concerning reputation and social image, such as the message about bravery and another about trusting science; and messages stating that vaccination is key to ending restrictions on personal freedom and economic activity implemented during the pandemic.

The second survey, conducted in September 2020, retested the baseline informational statement and the three best performing messages from the initial evaluation — which were those targeting community interest, embarrassment, and bravery — along with two revised messages concerning trust in science and personal freedom. It largely confirmed the results of the first survey, according to the authors.

“Vaccine acceptance research requires the same level of rigor and creativity as vaccine development research,” said Saad B. Omer, director of the Yale Institute for Global Health and co-author of the study. “This is one more example of faculty from various parts of Yale coming together to address a set of high priority questions in this pandemic.”

The simple informational message proved effective, increasing people’s intentions to get vaccinated by 6% over the control group in the nationally representative survey. The study showed that its efficacy was enhanced by adding language framing vaccination as a cooperative action aimed at protecting others, raising people’s intentions to get vaccinated by 10% over the control.

The message combining community interest with an appeal to the embarrassment an unvaccinated person would feel about getting others sick proved most effective in both surveys in motivating people to advise others to get the shots. It increased that intention by 14% over the control group among participants in the second survey.

In terms of provoking negative judgments of those who decline the vaccine, the messages urging people to trust the science and stating that refusing the vaccine is not brave were most effective in the second survey. While the message concerning science altered people’s beliefs about others who do not vaccinate, it was ineffective in getting people to change their minds about receiving the vaccine, the study showed.

The study’s other co-authors are Erin K. James, Scott E. Bokemper, and Alan S. Gerber, all of Yale.