Associations between parental generative artificial intelligence health-advice use and child vaccination uptake in Japan: an exploratory cross-sectional study.

BACKGROUND: Parents increasingly use generative artificial intelligence (AI) for health information, but evidence on parental AI use and childhood vaccination is limited. We examined exploratory associations between regular parental AI health-advice use and childhood vaccination in Japan. METHODS: This cross-sectional study analyzed 2025 nationwide survey data from children aged 1 to 17 years and parents, with a linked 2023-2025 sub-analysis. The exposure was regular parental use of generative AI for health advice at least a few times per month. Outcomes were age-appropriate measles-rubella (MR) vaccination and any mumps, influenza, or coronavirus disease 2019 (COVID-19) vaccination. Modified Poisson regression estimated adjusted prevalence ratios (aPRs) and 95% confidence interval (95% CI) with parent-level clustering and covariates. RESULTS: Among 8282 children and 5170 parents, 1278 (15.4%) had regular AI health-advice users as parents. AI use was not associated with age-appropriate MR vaccination (aPR 1.02; 95% CI 0.97-1.09), but was associated with three vaccines. The adjusted rates were 76.6 versus 72.7% (aPR 1.05, 95% CI 1.01-1.10) for mumps, 56.7% versus 49.0% (aPR 1.16, 95% CI 1.08-1.24) for influenza, 40.6% versus 30.9% (aPR 1.31, 95% CI 1.19-1.45) for COVID-19. The COVID-19 association was strongest among parents younger than 30 years (aPR 2.58; 95% CI 1.90-3.50; P for interaction < 0.001). In the linked sub-analysis, these associations persisted after adjustment for an available 2023 household-level prior vaccination marker and attitudes. CONCLUSIONS: Regular parental use of generative AI for health advice was associated with mumps, influenza, and COVID-19 vaccination, but not with age-appropriate MR vaccination. These exploratory, cross-sectional findings are observational associations. They may reflect digital health engagement, health information seeking, socioeconomic differences, or favorable attitudes, rather than vaccine-specific AI advice.