The United States is having its worst year for reported measles cases since 1991.
The CDC had recorded 3,471 confirmed cases in 2026 (as of September 18), already exceeding the 2,289 reported during all of 2025.
About 95% of this year’s cases were linked to outbreaks.
Measles was declared eliminated in the U.S. in 2000. That meant continuous domestic transmission had been interrupted, not that the virus had disappeared worldwide or could never return.
Travel-related infections can still introduce it. When the virus reaches communities with gaps in immunity, it can spread quickly.
Measles is extraordinarily contagious.
It spreads through the air and can remain infectious for up to two hours after an infected person leaves an area. Up to nine out of ten unprotected people close to someone with measles can become infected.
People can also spread the virus before the telltale rash appears.
The illness often begins with fever, cough, runny nose, and red, watery eyes. A rash follows, usually starting on the face and spreading downward.
Complications can include pneumonia, brain inflammation, and death. Young children, pregnant people, and people with weakened immune systems face greater risks.
Declining vaccination coverage is leaving more communities vulnerable. National averages can also hide local pockets where protection is much lower.
Two doses of the measles, mumps, and rubella vaccine are about 97% effective at preventing measles.
Checking vaccination records is a practical step, especially before travel or during a local outbreak. A healthcare professional can advise whether additional protection is needed.
If you suspect measles, call ahead before visiting a clinic so staff can arrange care without exposing other patients.
Learn more:
“Measles Cases and Outbreaks.” CDC