For Immediate Release

Contact: SHD.PIO@co.snohomish.wa.us

New Measles Case Identified in Snohomish County Infant

Snohomish County, WA —The Snohomish County Health Department was notified April 1, 2025, of a new positive measles case in a Snohomish County infant. The infant was likely exposed to measles during recent travel abroad. People who were at certain locations in Snohomish and King counties may have been exposed to measles. People who are vaccinated are well protected. Exposed individuals should check to make sure they have immunity against measles.

This is the second case of measles in an infant, and third case overall, in Washington State since January 1, 2025.   

Fortunately, the measles vaccine is highly effective. Two doses of the measles, mumps and rubella (MMR) vaccine provides about 97% protection against getting infected by measles. That protection lasts a lifetime.

“Our thoughts are with the child and their family, and we sincerely hope for a full and speedy recovery," said Dr. James Lewis, Health Officer for the Snohomish County Health Department. "Measles is a serious and highly contagious disease, and young children—especially those who are too young to be vaccinated—are particularly vulnerable to its complications. Vaccination remains our best protection against measles. We urge everyone, especially those who spend time around young kids, to ensure they are immune, both to protect themselves and to shield those who are most at risk. If you’re planning international travel, it’s also important to speak with your healthcare provider about what vaccines may be needed for you and your family to stay healthy and protected while abroad.”

Children need two doses of MMR vaccine: the first dose at age 12-15 months, and the second dose at age 4-6 years. Babies ages 6-11 months should get an early dose if traveling internationally. They will still need two additional doses later. 

“Measles is spreading around the U.S. and world. Vaccination is the most effective way to protect our children, not only from serious diseases like measles, but also to ensure they can attend school safely,” said Elysia Gonzales, Medical Epidemiologist for Public Health – Seattle & King County. “If you haven’t gotten around to taking your child in for vaccination, make an appointment with your child’s provider. In Washington State, all children under age 19 can get vaccines for free.” 

Locations of potential exposure to the public

Spread of measles can occur before people know they have the disease, before any rash appears.

The infant was at the following public locations before being diagnosed with measles. These times include the period when the individual was at the location and two hours after.  

Measles virus can remain in the air for up to two hours after someone contagious with measles leaves the area. Anyone who was at the following locations during the times listed could have been exposed to measles:

What to do if you were in a location of potential measles exposure

Most people in our area have immunity to measles through vaccination, so the risk to the general public is low. However, anyone who was in the locations of potential exposure to measles around the times listed should:

• Find out if you have been vaccinated for measles or have had measles previously. Make sure you are up to date with the recommended number of measles (MMR) vaccinations.
• Call a healthcare provider promptly if you develop an illness with fever or with an unexplained rash. To avoid possibly spreading measles to others, do not go to a clinic or hospital without calling first to tell them you want to be checked for measles after an exposure. It is also important to limit contact with others, especially those without known immunity, and to wear a well-fitting mask if you do need to go to a healthcare facility.

If you were at the locations at the times listed above and are not immune to measles, the most likely time you would become sick would be between April 3 and April 21, 2025. People with weakened immune systems may take longer to experience symptoms.

About measles

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.

Measles symptoms begin 7 to 21 days after exposure. Measles is contagious from about 4 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.

Complications from measles can happen even in healthy people, but those at highest risk include infants and children under 5 years, adults over 20 years, pregnant people, and people with weakened immune systems from medications or underlying disease.

If you are in one of these high-risk groups and were exposed to measles at one of these locations, be sure to contact your health care provider to discuss any steps you need to take to protect yourself or loved ones against complications from measles. 

Measles is preventable with the safe and highly effective measles, mumps and rubella (MMR) vaccine. According to the Centers for Disease Control and Prevention (CDC), two doses of the MMR vaccine are about 97% effective at preventing measles and that protection is long lasting.

For more information about measles and measles vaccination, including where to get measles vaccinations: Measles | Snohomish County Health Department, WA

This is a joint release sent with Public Health - Seattle and King County