Say It Right: Measuring the Impact of Different Communication Strategies on the Decision to Get Vaccinated

"Developing effective communication strategies is critical to maintain and expand the public health impact achieved by vaccines. Understanding strategies that are more effective in specific populations will help healthcare providers and stakeholders plan and implement effective interventions to ensure the maximum uptake of vaccines in different people, despite prior ideologies or beliefs."

Vaccine hesitancy has been associated with a reduction in vaccine coverage and outbreaks of vaccine-preventable diseases in several of the world's regions. Conducted in Brazil, the randomised experiment described in this paper investigated the effect of different communication strategies on the intention to receive a vaccine for a bogus emerging viral disease. It also explored interactions between communications strategies and prior vaccine-hesitant attitudes.

For the study, the researchers created four fictitious newspaper articles addressing an emerging bogus disease and its vaccine with the support of professional health journalists and disseminated them using social media tools. The articles were randomly assigned between August 2021 and January 2022 to 5,233 participants aged 18 or older. The first version focused on information about the disease; the second was akin to the first but included a case description and image; the third version focused on vaccine safety/efficacy; and the fourth version was like the third but included a case description and image. After reading a single version of the article, participants responded if they would take the vaccine and if they would vaccinate their children. The researchers used chi-squared tests for comparisons and investigated interactions with vaccine-hesitant attitudes.

Of the participants, 790 were caregivers of a child 5 years old or younger, and 15% had prior vaccine hesitancy. Although most declared the intention to take the vaccine, the percentage was highest among those exposed to the newspaper article focusing on the vaccine safety/efficacy with the case description and picture (91%; 95% confidence interval (CI) 89-92%), and it was lowest among participants exposed to the article focusing on the disease with no case description (84%; 95% CI 82-86%). In the analysis of intention to vaccinate their children, participants' intentions were also highest among those exposed to the newspaper article focusing on the vaccine safety/efficacy with the description and picture of a child affected by the disease, with statistically significant difference compared to the group exposed to the newspaper article focusing on the disease with the description and picture of a child affected by the disease. In addition, the researchers found evidence of effect modification by vaccine-hesitant attitudes, with a higher impact of communication focusing on vaccine safety/efficacy compared to that focusing on disease characteristics among hesitant participants.

Thus, in this study, exposure to information on vaccine efficacy and safety (science-based messaging) was associated with a higher likelihood of vaccination intention compared to exposure to information on disease severity (fear-based messaging). This effect was even higher among previously hesitant individuals. This finding may suggest that content that sounds intimidating or frightening (such as disease severity) may unexpectedly impair vaccine uptake among hesitant individuals, who could interpret the information as unfounded threats or ill-intentioned fake information. However, the study also highlights that the same vaccine-related message may result in an either increased, neutral, or decreased impact on vaccine uptake, depending on the audience, context, and messenger. This discrepancy reveals a familiar challenge to public health: one size does not fit all. To achieve the desired results, vaccine promotion messages should be delivered by trustworthy sources and use persuasive arguments, which can vary from audience to audience. Therefore, when planning communication strategies, the mere provision of information is not enough, and providers should consider the prior beliefs and attitudes of the audience as fundamental starting points.

In conclusion: "Communication strategies focusing on different aspects of the disease-vaccine duet may impact vaccine hesitancy, and storytelling/emotive imagery descriptions may improve risk perception and vaccine uptake. Moreover, the effect of message framing strategies may differ according to previous vaccine hesitant attitudes."