Communicating Vaccine Efficacy

These strategies from the social, behavioral, and decision sciences can help state, tribal, local, and territorial officials communicate with their target audiences about COVID-19 vaccines.

These strategies from the social, behavioral, and decision sciences can help public officials communicate with their target audiences about COVID-19 vaccines.

Producing Communication Content about Vaccine Efficacy, Effectiveness, and Safety
To produce responsive communications content on COVID-19 vaccine efficacy, follow these four steps:


Identify the outcomes most relevant to your audience through community partnerships What motivates the target audience to get vaccinated? Is it the efficacy, effectiveness, and safety of the vaccines? Or is it the chance to reconnect with family, friends, and social and cultural life? Form partnerships with community organizations to learn more about the audience’s concerns and motivations and use those to inform communication.


Summarize the evidence regarding those outcomes Collect, analyze, and share real-world evidence on vaccine effectiveness, safety, and distribution. Know the quality of that evidence, such as the size of clinical trial samples, the quality of measurements, and the relevance of changes in the world (e.g., new variants) or in the vaccines (e.g., quality control problems). Communicating about the institutions involved in the vaccine program may also be important, particularly for people who interpret their actions in the context of current and historical inequities.


Identify the most relevant subset of evidence People have limited attention spans for processing new information. Identify what information is most relevant to the audience’s decision making, and then present that information using familiar frames of reference and culturally appropriate terms. For example, Drug Facts boxes, patterned after Nutrition Facts boxes, have been effective at communicating clinical trial results.


Evaluate messages before dissemination To ensure that the messages are understood as intended, conduct think-aloud interviews, in which individuals from the target audience read a draft and share how they interpret each line, including what is unclear. When community partners help recruit draft readers, these interviews can help build relationships with target communities by fostering engagement in vaccine promotion.

Designing Communication Content

The following five design principles are particularly relevant to communicating about how well COVID-19 vaccines work.


Define terms clearly Clinical trials for the currently authorized vaccines defined their clinical endpoints for efficacy differently, which can lead to confusion among the public. Reduce that confusion by consistently focusing messages on the same clinical endpoints, such as severe illness, hospitalization, or death.


Use numbers to describe quantities Verbal quantifiers (e.g., “rare” side effect, “likely” success, “probable” cause) communicate poorly. The same word can mean different things to different people and to the same person in different settings. Instead, use numbers to describe quantities.


Compare options clearly To reduce their cognitive load, people sometimes focus on one option, leading them to favor it over others. Well-designed tables can facilitate comparing options in terms of their respective advantages and disadvantages. For example, they can encourage looking at the various effects of both choosing and declining vaccination.


Present all relevant outcomes Individuals may weigh the importance of clinical outcomes differently. Unless one option is better than all others in every respects, communications need to present evidence regarding all outcomes (e.g., severe symptoms vs. hospitalization).


Communicate uncertainty and anticipate changes Public trust can be undermined when officials suddenly change course, even if the changes are necessary in light of new information. Decision makers can reduce threats to their credibility by communicating how much they know, what they do not know, and when they expect to know more. For example, public officials can acknowledge that some cases of mild disease are to be expected among fully vaccinated people, and also that the absolute number of fully vaccinated people experiencing mild disease is expected to increase as more people become vaccinated. By establishing this expectation, public officials can maintain their credibility with the public when these situations do occur.


Learn More

These rapid expert consultations were produced by SEAN (supported by the National Science Foundation and the Alfred P. Sloan Foundation) and the Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats (supported by the Department of Health and Human Services and the Office of Science and Technology Policy).

Read the guidance online at

How can SEAN help?

Are you a policy maker? Do you have a question you need answered? SEAN will consider the most pressing questions and engage the nation’s experts to focus on your challenges. Contact us at or 202-334-3440.

SEAN is a network of experts in the social, behavioral, and economic sciences poised to assist decision makers at all levels as they respond to COVID-19. The network appreciates any and all feedback on its work. Please send comments to