Intention to vaccinate children against measles: findings from a national survey in the United States.

Background: The United States is currently experiencing the largest surge of measles cases since 2000, with over 2855 cases reported across the country since January 2025. Though the measles, mumps, and rubella (MMR) vaccine is recognized as the most effective protection against measles, rates of MMR coverage among children under the age of five have declined in several US states. Across the US, attitudes towards measles and intention to vaccinate are not well understood. Methods: We conducted a nationally representative survey assessing measles knowledge, attitudes, and intention to vaccinate among US adults (18+). Our primary outcome was assessing whether respondents would be willing to vaccinate a child under the age of five against measles if recommended to do so by a health professional. We also assessed participant knowledge of measles, their perception of measles risk, the degree to which they believed the threat of measles was being exaggerated, and whether participants indicated they would be willing to receive the MMR vaccine as an adult if recommended to do so by a healthcare professional. Respondents were stratified by whether they had children of any age, and analyses were weighted based on age, sex, and race estimations sourced from the American Community Survey 2022. Proportions, means, and 95% confidence intervals (CI) were calculated for intention to vaccinate, trust in sources of information, self-assessed knowledge, risk perception, perceived exaggeration of threat, self-efficacy, and measles and influenza vaccination status, and adjusted according to survey weights. Findings: A total of 1166 respondents completed the survey. Of those who completed the survey, 53% (weighted percentage, unweighted n = 620) were male, 70% (850) were over the age of 36, 16% (182) were Black or African American, 14% (164) were Hispanic, and 85% (1105) had some college education. Half (50%, 95% CI: 47-53) reported an average knowledge of measles and 81% were aware of the MMR vaccine. Overall, 79% (95% CI: 76-81, 914) were willing to vaccinate a child under five against measles, including 82% of parents with children of any age, and 75% of non-parent respondents. Respondents without children were significantly less likely to vaccinate a child against measles (aOR: 0.67, 95% CI: 0.36-0.98), as were those who believed the threat of measles was being exaggerated (aOR: 0.19, 95% CI: 0.12-0.31). Respondents who reported a higher perceived risk of measles were more likely to vaccinate children against measles (aOR: 1.5, 95% CI: 1.1-2.0) Intention to vaccinate also varied geographically. Interpretation: These results show that while childhood measles vaccination remains the social norm with close to 80% intention, there is an important minority of US adults who are not willing to vaccinate children against measles even if recommended to do so. Measles requires an overall vaccination rate of over 90% to ensure population-level protection; a 20% minority of those not willing to vaccinate is sufficient to breach this nominal threshold of herd immunity. Efforts to improve attitudes towards and uptake of the MMR vaccine should leverage the social norm of childhood vaccination and school-based vaccine requirements while targeting populations who are less willing to vaccinate. Funding: No external funding was provided to support this study.