National U.S. survey links science perceptions to partisan gaps in vaccine judgments

A national survey of 1,763 U.S. adults found that perceptions of science and scientists were associated with whether respondents considered three vaccines safe and effective, and that these broader perceptions statistically accounted for partisan differences in judgments of the MMR and seasonal flu vaccines. Political affiliation remained associated with perceptions of the Covid-19 vaccine after the researchers accounted for the science-related attitudes they measured.

The study, led by researchers from the Annenberg Public Policy Center at the University of Pennsylvania, was published in the American Journal of Public Health. It was an observational analysis of a probability sample, so its findings identify associations rather than establishing that attitudes toward science caused particular vaccine judgments. The results also apply to the three vaccines and survey period examined and do not directly measure vaccination behavior or changes over time.

Researchers used data collected in November 2024 through the Annenberg Science and Public Health survey. The national probability sample of 1,763 empaneled U.S. adults rated the safety and effectiveness of the measles, mumps and rubella vaccine, the seasonal flu vaccine and the Covid-19 vaccine. Respondents also answered questions about their views of science and scientists.

To measure those views, the team used the Factors Assessing Science’s Self-Presentation model, or FASS, introduced by Annenberg researchers in 2023. It considers five aspects: whether scientists are credible, prudent and unbiased, and whether science is beneficial and self-correcting. This allowed the analysis to examine specific attitudes rather than combine them into a single measure of trust in science.

On four-point scales, the MMR vaccine received the highest average ratings for both safety and effectiveness, at 3.54 and 3.63, respectively. The flu vaccine followed with an average safety rating of 3.41 and an effectiveness rating of 3.03. The Covid-19 vaccine had the lowest averages among the three: 2.98 for safety and 2.81 for effectiveness. These figures describe respondents’ perceptions, not estimates of the vaccines’ clinical performance.

Democrats rated the MMR, flu and Covid-19 vaccines as safer and more effective than Republicans did. After the researchers statistically accounted for respondents’ broader perceptions of science and scientists, the partisan differences for MMR and flu were no longer statistically significant. For Covid-19, however, political affiliation remained significantly associated with perceived safety and effectiveness.

One FASS attribute was consistently associated across the results: viewing science as beneficial was associated with believing that all three vaccines were both safe and effective. Other attributes, including scientists’ perceived credibility, prudence and lack of bias, were associated with some vaccine evaluations but not others. For the Covid-19 vaccine, the study’s results suggested that positive perceptions of science and scientists were more strongly associated with vaccine perceptions among Republicans than among Democrats.

The researchers said the vaccines’ different histories may help explain why the pattern varied. They noted that MMR has been widely used for decades, while the Covid-19 vaccine was introduced during an intensely polarized pandemic and became the subject of attacks by political figures and partisan media. They also noted that seasonal flu vaccine effectiveness varies by season, partly because of how well the vaccine matches circulating strains. The study did not directly test these historical or political explanations.

On that basis, the researchers suggested that vaccine communication should account for the particular vaccine, its history, perceived safety and effectiveness, and the political affiliation of the intended audience. For Covid-19, they said communications may need to address concerns about scientific bias and could explain mechanisms through which science identifies and corrects bias. The authors emphasized that further research would be needed to test whether those approaches are effective, and said responsible communication consistent with scientific evidence is important when vaccines become politically polarized.

Subject of Research: A cross-sectional U.S. survey examining associations among political affiliation, perceptions of science, and perceived vaccine safety and effectiveness.

Article Title: Views of science help explain partisan differences over vaccine safety and effectiveness

Article References: Views of science help explain partisan differences over vaccine safety and effectiveness. Original publication (Bibliographic details unavailable.)

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Keywords: vaccine perceptions, science communication, partisan differences, MMR vaccine, flu vaccine, Covid-19 vaccine, vaccine safety, vaccine effectiveness, FASS model, survey research, Views, science