Measles epidemiology —
United States, 2025

Epidemiologic overview (2025) As of October 7, 2025, a total of 1,563 confirmed measles cases have been reported in the United States, spanning 42 jurisdictions, including major metropolitan areas such as New York City. This represents a sharp increase compared with 285 cases in 2024 and 59 cases in 2023. Most cases in 2025 occurred in the context of outbreaks (≥3 related cases). Forty-four outbreaks have been identified to date, accounting for 87% (1,355 of 1,563) of all cases—up from 16 outbreaks and 69% outbreak-associated cases in 2024. Most outbreaks remain small (fewer than six cases), though larger clusters have occurred in under-vaccinated communities. Age, vaccination status, hospitalizations, and deaths Measles affects all age groups but disproportionately impacts children and adolescents: <5 years: 423 cases (27%) 5–19 years: 614 cases (39%) ≥20 years: 518 cases (33%) Age unknown: 8 cases (1%) Vaccination status among confirmed cases indicates persistent immunity gaps: Unvaccinated or unknown: 92% One MMR dose: 4% Two MMR doses: 4% Hospitalization...