On Jan. 15, 2026, the Snohomish County Health Department in Washington has confirmed three new measles cases this week in local children who were exposed to a contagious family visiting from South Carolina. These three new cases amount to an outbreak – a sign the disease is now spreading locally.

The children tested positive for the virus that causes measles on Wednesday, Jan. 14. They had experienced fever, cough and rashes consistent with measles. The children were unvaccinated for protection against the disease.

Most people in our area have immunity to measles through vaccination, so the risk to the general public is low. Check your status for the MMR (measles, mumps and rubella) vaccine. It is a safe and highly effective vaccine that lasts a lifetime and offers 97% protection. If you are not immune to measles, or don’t know your vaccination status, please get vaccinated when you can and see the list below for locations and times of potential exposure.

Last week, the Snohomish County Health Department and Public Health – Seattle & King County were notified that three members of a South Carolina family – one adult and two children – were infectious while visiting King and Snohomish counties from Dec. 27, 2025, through Jan. 1, 2026. The family visited multiple locations in Everett, Marysville and Mukilteo while contagious – but before being diagnosed – with measles. They also traveled through Seattle-Tacoma International Airport and visited a car rental facility near the airport.

The largest active measles outbreak in the U.S. is in South Carolina, where 434 cases of measles have been reported since October, according to the South Carolina Department of Public Health Department.

Measles is a highly contagious and potentially severe disease that causes fever, rash, cough, runny nose and red, watery eyes. If one person has it, up to 9 out of 10 people nearby will become infected if they are not protected. It mainly spreads through the air after a person with measles coughs or sneezes.  

The incubation period for measles is 10 to 14 days from exposure to onset of symptoms, with a range of 7 to 21 days. For people exposed at the schools, that would be through Jan. 30. For those who were at Swedish Mill Creek, that would be through Feb. 3. Measles is contagious from about 4 to 5 days before the rash appears through 4 days after the rash appears. People can spread measles before they have the characteristic measles rash.  Measles can lead to ear infections, diarrhea, pneumonia, and rarely, encephalitis (brain inflammation) or death.