First Measles Case Of 2025 Confirmed In King County

Public Health – Seattle & King County has confirmed the first measles case of 2025 in a King County infant, with potential exposure at multiple public locations. Officials urge residents to check their vaccination status, as measles is highly contagious and can spread rapidly among those who are not immunized. The infant may have been exposed to the virus during recent international travel.

“Measles is easily spread from person to person. If one person has it, up to 9 out of 10 people nearby will become infected if they are not protected,” said Dr. Eric Chow, Communicable Disease Chief for Public Health – Seattle & King County. “We are seeing increases in measles cases within and outside the U.S. Talk to your doctor about checking your vaccination status and get vaccinated now if you aren’t already protected.”

Measles remains one of the most infectious diseases, but it is preventable with the measles, mumps, and rubella (MMR) vaccine. Two doses of the MMR vaccine provide about 97% protection against measles, and immunity lasts a lifetime.

In 2024, three measles cases were reported in King County. Health experts emphasize that herd immunity, which helps prevent widespread outbreaks, requires about 95% of the population to be vaccinated. When vaccination rates drop, the risk of larger and more frequent outbreaks increases.

Current estimates for King County show that 87% of 2-year-olds have received at least one dose of the MMR vaccine, while 72% of 4–6-year-olds have received the recommended two doses. Infants and children under five are at higher risk of severe complications from measles. Receiving at least one dose of MMR early provides crucial protection. Parents are encouraged to ensure their children receive the second dose as soon as they are eligible, rather than waiting until school enrollment.

Measles can spread before symptoms appear, making early detection and vaccination critical. The measles virus can linger in the air for up to two hours after an infected person has left an area. Individuals who were at the following locations during the listed times may have been exposed:

February 20, 6:00 PM – 9:00 PM: Apple Store at Bellevue Square, 213 Bellevue Square, Bellevue, WA 98004

February 21 – 22, 10:30 PM – 2:15 AM: Seattle Children’s Hospital Emergency Department, 4800 Sand Point Way NE, Seattle, WA 98105

February 24, 1:00 PM – 4:15 PM: Allegro Pediatrics – Bothell, 11724 NE 195th St, Ste 100, Bothell, WA 98011

February 25, 1:00 PM – 4:00 PM: Northwest Asthma & Allergy Center, 8301 161st Ave NE, Ste 308, Redmond, WA 98052

February 25, 2:30 PM – 5:30 PM: Seattle Children’s Hospital Emergency Department, 4800 Sand Point Way NE, Seattle, WA 98105

The three medical facilities listed are directly notifying patients and families who may have been exposed, providing guidance on symptoms to watch for and next steps.

Most people in King County have immunity through vaccination, so the overall risk to the general public is low. However, anyone who was at the exposure locations during the listed times should verify their vaccination status and ensure they are up to date on measles (MMR) vaccinations.

Individuals should monitor for symptoms such as fever, rash, cough, runny nose, and red, watery eyes, which may develop seven to 21 days after exposure. Anyone experiencing symptoms should call a healthcare provider rather than going directly to a clinic or hospital.

To prevent further spread, medical facilities should be contacted in advance to inform them of possible measles exposure. If seeking care, individuals should limit contact with others and wear a mask.

For those not immune, the highest risk of developing measles will be between February 27 and March 18, 2025. Individuals with weakened immune systems may develop symptoms later.

Measles is a highly contagious viral disease that spreads through the air when an infected person coughs or sneezes. Symptoms typically begin seven to 21 days after exposure and can lead to serious complications. Measles is contagious from about four days before the rash appears to four days after.

Potential complications include ear infections, diarrhea, pneumonia, encephalitis (brain inflammation), and, in rare cases, death. Infants, young children, pregnant individuals, and those with weakened immune systems face the highest risk of severe illness.

If you fall into one of these high-risk groups and may have been exposed, contact a healthcare provider immediately to discuss steps to reduce potential complications.

Measles is preventable with the MMR vaccine, which is safe and highly effective.

“We are not just asking for change; we are demanding accountability,” said Dr. Chow. “This bill makes it clear that public safety is not about more policing but about creating strong, thriving communities. It’s about smart investments, bold policies, and ensuring that every community—especially those most impacted by systemic injustice—has the resources and support they deserve.”

Public Health – Seattle & King County urges all residents to verify vaccination records and get the MMR vaccine if they are not fully immunized. Ensuring children receive both doses on time and encouraging community-wide immunization efforts are critical to maintaining herd immunity and preventing outbreaks.

For more information about measles, vaccination locations, and updates, visit www.kingcounty.gov/measles.