The US Centers for Disease Control and Prevention (CDC) reported 4,588 confirmed measles cases in the United States in 2026 as of 22 October, in its update of 23 October 2026. The cases were reported by 47 jurisdictions, and 18 were among international visitors. The CDC lists 3 deaths in 2026, a number it says is subject to change.
For comparison, the CDC recorded 2,289 confirmed cases across the whole of 2025 and 285 in 2024. There have been 43 new outbreaks reported in 2026, and 96% of confirmed cases this year (4,404 of 4,588) are outbreak-associated.
Measles was declared eliminated in the United States in 2000. The CDC links the recent rise in cases to falling vaccination coverage and increasing measles activity worldwide. According to the CDC, MMR vaccine coverage among US kindergarteners fell from 95.2% in the 2019 to 2020 school year to 92.4% in the 2025 to 2026 school year, below the 95% coverage target, leaving approximately 280,000 kindergarteners at risk.
The CDC states that two doses of MMR vaccine are 97% effective at preventing measles and one dose is 93% effective, and that breakthrough infections account for approximately 10% of measles infections, consistent with previous years.