As measles spreads across the U.S., a few fully vaccinated people have contracted rare breakthrough cases. Here's what to know and why vaccination is still important.

Measles spreads quickly, and can expose others at hospitals and clinics. Experts urge precautions for suspected cases to protect vulnerable patients like newborns.

The CDC also recommends that people who had an allergic reaction to the first MMR vaccine hold off on getting the second dose. In addition, people with any "severe, life-threatening" allergies should consult their doctor before getting vaccinated because it may not be safe.

An out-of-state visitor with measles could have exposed others at a Mercer County medical center last week, the state Health Department announced Friday. The patient visited the emergency department at Capital Health Medical Center in Hopewell from 5:15 p.m. on March 22 to 1:30 a.m. the following morning, according to the state announcement.

A person not infectious in Minnesota may have exposed people while traveling in Washington, D.C. The state health department says the person was vaccinated but still advises vaccines protect most people from measles.

No, there have been no measles cases reported in Wisconsin in 2025. There have been 378 measles cases in the U.S. reported as of March 20, U.S. Centers for Disease Control and Prevention data shows. The agency notes only confirmed cases are included in data, though it is "aware of probable measles cases" reported by other jurisdictions.

Anyone on Amtrak Northeast Regional Train 175 on March 19 between 7:30 p.m. and 1:30 a.m. should contact their doctor for possible testing.

Earlier this year, the Texas Department of State Health Services reported an outbreak of measles that began in the South Plains and Panhandle regions of Texas. As of Friday, March 28, 400 cases have been identified since late January and 41 of those diagnosed have been hospitalized.