Encouraging COVID-19 Vaccine Uptake Through Effective Health Communication

"...results offer a potential path forward for health communicators hoping to devise messaging strategies aimed at increasing vaccine uptake."

Previous research suggests that many people in the United States (US) either plan to refuse a COVID-19 vaccine or are hesitant about it, thereby jeopardising the herd immunity necessary to combat the pandemic. This study investigates the effectiveness of three different health communication frames (pro-vaccine messaging tactics) hypothesised to increase vaccine intention. It also discusses how the findings could be incorporated into future research and practical efforts to increase public willingness to vaccinate against COVID-19.

In a large (N = 7,064) and demographically representative survey experiment, conducted from July 8-20 2020, the researchers randomly assigned respondents to read pro-vaccine communication materials featuring messages that emphasise either:

1. Personal health risks (i.e., the possibility of getting seriously sick);
2. Economic costs (i.e., the financial burdens associated with the economy "shutting down" in order to contain the virus' spread); or
3. Collective public health consequences of not vaccinating (i.e., the possibility of infecting others, including vulnerable populations).

They also randomly varied:

• The message source (i.e., ordinary people vs. medical experts) - Doctors and other medical experts may seem like intuitive and potentially effective communicators, but trust in scientific experts is far from unanimous, and those who distrust scientific experts have been shown to be particularly resistant to evidence-based messaging originating from expert sources; and
• Availability of information about the process of determining vaccine safety and efficacy via clinical trials (i.e., whether or not they preempt or "pre-bunk" concerns that a vaccine developed in an accelerated timeframe (i.e. "Operation Warp Speed") will not be safe and effective) - Notably, pre-bunking necessarily implies providing the public with the very misinformation it hopes to counteract and so risks potentially "backfiring" (i.e., people accept the misinformation presented) or may fail to move opinion.
• They also explored whether partisan (political) polarisation in vaccination intentions would moderate treatment effects: "Will the efficacy of pro-vaccination messages that vary in source, frame, and/or the inclusion of pre-bunking information be more effective for Democrats vs. Republicans?"

All respondents not assigned to the control group (who read a short story about baseball) read a short newspaper opinion piece about the importance of receiving a COVID-19 vaccine, when it becomes available.

Respondents were asked, "When a vaccine for the novel coronavirus (COVID-19) becomes widely available, how likely are you to request to be vaccinated?" Just 42% of respondents indicated they were "very likely" to get vaccinated, while an additional 30% indicated they were somewhat likely to do so.

The results suggest that, among conditions that featured no pre-bunking information, appeals to the personal health risks of not vaccinating were positively and significantly associated with increased vaccine intention for both expert and lay sources. Specifically, they led to a 7% and 6% increase in the likelihood of being "very likely" to receive the vaccine, respectively. Also, exposure to lay messages about the collective health risks of not vaccinating are associated with a 5% increase in the likelihood of being "very likely" to vaccinate. Among conditions that feature pre-bunking information, the only statistically significant increase in vaccine intention across variations on the source and arguments presented in each message occurred with messages emphasising the collective health risks of failing to vaccinate, sourced by ordinary people.

Surprising to the researchers was the finding that economic cost frames had no discernible effect on vaccine intention. In addition, despite sharp partisan polarisation in public vaccination intentions (there was an expectation that Republicans might be less receptive than Democrats to the study's messages), the researchers found that the effects were no different for Democrats, Republicans, and Independents alike.

Thus, based on the results, the researchers recommend focusing on either the personal or community health risks of the failure to vaccinate; the latter may be particularly effective at increasing intention among those least likely to vaccinate. The finding that the addition of information designed to assuage respondents' potential fears about the safety of expedited clinical trials weakened treatment effects suggests that it would be better to avoid attempting to preempt concerns about the rigours of clinical trials. Furthermore, this study documents that messages from ordinary people can be effective at increasing intended vaccine uptake.

Due to limitations discussed in the paper, the researchers see their study "as not the final word on how to effectively boost COVID vaccine uptake, but instead as a starting point for future efforts to unpack the conditional effectiveness of personal and collective public health risk frames, and to consider altering other design elements not presented in this paper." Among the suggestions for future research:

• Determine if certain types of communicators within each category (ordinary people vs. experts) are better at conveying messages that others. For example, on the non-expert side, it could be helpful to understand the value of contextual cues of the messenger (e.g., gender, partisanship, and race; what about use of a celebrity?) to identify the best communicators for the importance of vaccination.
• Determine how repeated message exposure and exposure to countervailing messages in the information environment influence vaccination intention. Moreover, future research could explore how COVID-19 vaccination messages interact and influence behaviour.
• Understand why skeptics are hesitant to vaccinate, and design targeted interventions to appeal specifically to these harder-to-move individuals. Given the safety and efficacy concerns of individuals in this hesitant group, particular emphasis could be placed on interventions designed to ease these concerns.

In conclusion: "both lay and expert health communicators can improve vaccination rates by highlighting the personal health risks and collective public health consequences of COVID-19 vaccination..."