County surveillance failed to detect that measles transmission reached epidemic threshold in schools

A nationwide analysis of measles vaccination records from more than 50,000 US schools shows that measles transmission risk crossed the threshold that can lead to epidemics at the school level in the 2–3 years before the 2025–2026 outbreaks, whereas county-level estimates always remained below that threshold. This is a preview of subscription content, access via your institution Access options Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $32.99 / 30 days cancel any time Subscribe to this journal Receive 12 print issues and online access $259.00 per year only $21.58 per issue Buy this article - Purchase on SpringerLink - Instant access to the full article PDF. USD 39.95 Prices may be subject to local taxes which are calculated during checkout References Centers for Disease Control and Prevention. Measles cases and outbreaks. CDC https://www.cdc.gov/measles/data-research/index.html (2026). This is the source of the primary surveillance data for the >3,500 confirmed US cases of the 2025–2026 measles epidemic. Do, L. A. H. & Mulholland, K. Measles 2025. N. Engl. J. Med. 393, 2447–2458 (2025). A current review of the drivers of measles resurgence, including vaccine hesitancy and the erosion of population immunity. Masters, N. B. et al. Fine-scale spatial clustering of measles nonvaccination that increases outbreak potential is obscured by aggregated reporting data. Proc. Natl Acad. Sci. USA 117, 28506–28514 (2020). This study establishes that aggregated reporting hides fine-scale clustering of susceptibility — the principle that our study validates empirically across nationwide multiscale data. Glasser, J. W., Feng, Z., Omer, S. B., Smith, P. J. & Rodewald, L. E. The effect of heterogeneity in uptake of the MMR vaccine on the potential for outbreaks of measles: a modelling study. Lancet Infect. Dis. 16, 599–605 (2016). This foundational modeling study shows that clustering of unvaccinated individuals can sustain outbreaks even when average coverage seems adequate. Hackell, J. M. et al. Medical vs nonmedical immunization exemptions for child care and school attendance: policy statement. Pediatrics 156, e2025072714 (2025). This article provides current policy context for the exemption differences underlying divergent state susceptibility trajectories. Additional information Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This is a summary of: Chen, S. & Bento, A. I. County, district and community-level measles transmission in the United States in 2013−2025. Nat. Med. https://doi.org/10.1038/s41591-026-04561-w (2026). Rights and permissions About this article Cite this article County surveillance failed to detect that measles transmission reached epidemic threshold in schools. Nat Med (2026). https://doi.org/10.1038/s41591-026-04612-2 Published: Version of record: DOI: https://doi.org/10.1038/s41591-026-04612-2