MMR vaccine hesitancy in a polarized information ecosystem: Results from a cross-sectional survey of US adults.

OBJECTIVES

To characterize MMR vaccine hesitancy in US adults amid the 2025 measles outbreaks, with specific focus on the role of an individual's media habits.

METHODS

We conducted an online panel survey in August 2025, with 2970 US-based, English-speaking adults (≥18 yrs). We conducted bivariate analyses with chi-square tests to characterize differences between hesitant and non-hesitant adults. We used logistic regression modeling to identify factors associated with MMR hesitancy.

RESULTS

Overall, 17% (n = 501) of adults believed the risks of MMR outweighed the benefits. Most adults engaged with a wide range of digital media, but engagement with "new" right media outlets (e.g., Breitbart) was associated with increased odds of MMR hesitancy (adjusted odds ratio [AOR] = 2.08; 95% confidence interval [CI] = 1.64, 2.82). Seeking health information from non-authoritative sources both online (e.g., social media influencers AOR = 1.41; CI = 1.06, 1.98; alternative health newsletters AOR = 1.39; CI = 1.01, 1.90) and offline (e.g., alternative health practitioners AOR = 1.70; CI = 1.31; 2.35) was also associated with increased odds of MMR hesitancy.

CONCLUSIONS

In an increasingly fragmented information ecosystem where news coverage of public health events is politically polarized, individual media and health information seeking preferences emerge as key correlates of MMR vaccine hesitancy. Specifically, engagement with "new" right media and seeking health information from alternative healthcare providers were the strongest associated factors with MMR hesitancy, whereas reliance on physicians for health information had the most protective effect.