The United States has now recorded 2,777 confirmed measles cases in 2026, according to the latest CDC data, making this the worst year for the disease since it was declared eliminated domestically in 2000. The tally already exceeds the total for all of 2025, which itself had been the highest in more than three decades.
Cases have been reported across 47 states and the District of Columbia, plus 16 additional cases among international visitors. The CDC says 36 separate outbreaks have driven the surge, with 94% of this year's cases — 2,614 of 2,777 — tied to identifiable outbreak clusters rather than isolated infections.
Health officials point to falling childhood vaccination rates as the primary driver. MMR vaccine coverage among U.S. kindergartners has slipped from 95.2% in the 2019–2020 school year to 92.4% in 2025–2026, according to CDC survey data — well below the roughly 95% threshold epidemiologists say is needed to sustain herd immunity and prevent sustained transmission. Officials estimate that gap now leaves close to 280,000 kindergartners without documented protection against the virus.
The rise has unfolded gradually but steadily: from 59 cases and four outbreaks in 2023, to 285 cases in 2024, to 2,289 in 2025, and now to this year's total with more than four months still remaining on the calendar. Measles remains one of the most contagious pathogens known, capable of lingering in airspace for up to two hours after an infected person leaves a room, and can cause severe complications including pneumonia and encephalitis, particularly in young children.
Public health authorities are urging parents to confirm their children's MMR vaccination status ahead of the school year, and are continuing to trace exposure sites tied to the active outbreak clusters as the fall respiratory illness season approaches.
