Since Trump took office in 2025, the U.S. has recorded more confirmed measles cases than in the previous 20 years combined. With more than two months to go in 2026, the US has already DOUBLED its 2025 total.
Last week, the US topped 5,000 cases for the first time since 1991. Next week, the Pan American Health Organization is virtually certain to declare that the United States has lost its measles elimination status, which it has held since 2000.
Question What proportion of US adults endorse non–evidence-based beliefs about autism risk, and what characteristics are associated with these beliefs?
Findings In this cross-sectional survey study of 30 288 US adults, approximately one-quarter of respondents endorsed childhood vaccinations or acetaminophen use during pregnancy as autism risk factors. This endorsement was more common among individuals with particular sociodemographic characteristics and political affiliations, whereas greater trust in scientific and medical institutions was associated with lower rates of endorsement.
Meaning Results suggest that non–evidence-based beliefs about autism risk factors are common among US adults and highlight the need for targeted public health efforts to address these beliefs.
From the article:
Belief in childhood vaccination as a risk factor ...Adding political party to this model, all other affiliations were less likely to endorse this belief than strong Republican (aORs, 0.23-0.71; strong Republican vs strong Democrat, aOR, 3.83; 95% CI, 3.47-4.24; eFigure 3 in Supplement 1).
...
Trust in Donald Trump was associated with a significantly greater likelihood of such beliefs (vaccination aOR, 4.51 [95% CI, 4.13-4.91]; acetaminophen aOR, 4.50 [95% CI, 4.11-4.93]).
Abstract
Importance With the rise of misinformation about autism risk, including recent statements from US government officials, the extent to which the public understands environmental autism risk factors is not known.
Objective To characterize beliefs about autism risk factors among US adults and identify characteristics influencing these beliefs.
Design, Setting, and Participants This cross-sectional survey study used data from an internet-based survey of adults aged 18 years or older residing in all 50 US states and the District of Columbia and was administered between December 18, 2025, and January 27, 2026. Multiple regression models assessed sociodemographic and other individual characteristics, including political affiliation and trust in institutions, for association with endorsement of misinformed beliefs.
Main Outcomes and Measures The primary outcome was endorsement of individual risk factors, scored on a 5-point Likert scale from definitely false to definitely true.
Results Of the 30 388 adults who completed the survey, 100 did not provide an answer to the childhood vaccination item, leaving 30 288 in the analysis. Among the 30 288 participants (mean [SD] age, 46.6 [15.9] years), 13 702 (45.2%) identified as men, 16 393 (54.1%) as women, and 193 (0.6%) as nonbinary. The most commonly endorsed cause was genetic factors (20 380 of 30 254; unweighted, 67.4%; weighted, 66.7%), an evidence-based risk factor. However, 8370 of 30 288 (unweighted, 27.6%; weighted, 26.6%) endorsed childhood vaccinations and 7140 of 30 211 (unweighted, 23.6%; weighted, 23.1%) endorsed acetaminophen in pregnancy as autism risk factors. In regression models, endorsement of vaccine-autism risk beliefs was greatest among adults aged 35 to 44 years (vs 18 to 24 years, adjusted odds ratio [aOR], 1.64; 95% CI, 1.44-1.86) and lowest among those aged 65 years and older (aOR, 0.64; 95% CI, 0.55-0.74). Endorsement was also associated with men (aOR, 1.26; 95% CI, 1.19-1.34), African American or Black race (compared with White race, aOR, 1.25; 95% CI, 1.15-1.35), Hispanic ethnicity (aOR, 1.13; 95% CI, 1.03-1.24), and strength of Republican political affiliation (strong Republican vs strong Democrat, aOR, 3.83; 95% CI, 3.47-4.24). More frequent social media use was associated with lower odds of endorsing misinformation (multiple times daily vs less than weekly, aOR, 0.72; 95% CI, 0.66-0.78).
Conclusions and Relevance Results of this survey study suggest that non–evidence-based beliefs about autism risk were prevalent among US adults and were strongly associated with sociodemographic differences and political affiliation. Limiting public health impact of such non–evidence-based information will likely require targeted interventions that recognize the heterogeneity of such beliefs.

