KFF Tracking Poll on Health Information and Trust: Update on Common Vaccine Myths

Key Findings

• — 20% of all US adults report using AI tools or chatbots at least weekly for health advice.
• — 35% of weekly AI-for-health users say it is probably or definitely true that MMR vaccines have been proven to cause autism, against 20% of those who never use AI for health advice.
• — The same comparison for social media is 37% weekly users against 16% never-users, so the AI gap is real but smaller than the social-media gap.
• — Weekly AI-for-health users were also more likely than never-users to believe that mRNA vaccines alter human DNA.
• — Weekly-plus AI users were somewhat more likely to fall in the poll's 'mixed middle' uncertainty group.
• — The associations persist controlling for age, race and ethnicity, education and partisanship.

Methodology Notes

n = 2,480 US adults: address-based sample n = 1,977 plus an RDD prepaid-cell sample n = 503; fielded 7 to 31 May 2026, online and by telephone; 2,407 in English and 73 in Spanish; weighted to CPS 2025 with 2024 vote recall; margin of error plus or minus 3 points on the full sample. Cross-sectional and correlational: the poll cannot say whether AI use spreads the belief or whether people who already hold the belief seek out AI. Landing page fetched and the n, field dates and percentages verified in the text. Distinct from the held March 2026 KFF poll on AI health information and advice (different field window, different instrument).

Sources