DuPage County confirms first case of measles in 2026

The DuPage County Health Department (DCHD) has confirmed a measles case in a vaccinated DuPage County resident who recently returned from international travel.

This is a rare breakthrough infection. While measles after vaccination is uncommon, it can occur when there is intense or prolonged exposure to a person with measles. Even when breakthrough infections occur, there are benefits to vaccination.

Vaccinated individuals who develop measles usually have a milder illness and are less likely to experience complications.  They also may be less likely to spread the virus to others.

“Our community’s safety is our priority. Our team is actively working on following up with individuals who may have been potentially exposed,” said Adam Forker, executive director, DuPage County Health Department. “Vaccination continues to provide strong protection, even in a rare breakthrough case.”

DCHD is working with healthcare and public health partners to contact anyone who may have been exposed.

Current public exposure locations for this case can be found at the  Chicago Department of Public Health’s Measles: Get The Facts webpage. DCHD is coordinating direct outreach to people who may have been exposed in healthcare locations in DuPage County.

What to do if you were exposed to measles

Most people in DuPage County are protected through vaccination, so the risk to the public is low. However, anyone who was at O'Hare Airport, Terminal 5 on Thursday, Oct. 15 between 4:20 and 7:00 p.m. should:

Report your exposure:

• If you are a DuPage County resident, call DCHD at (630) 682-7400. Health officials will follow up if additional steps are needed.
• If you live in another county, contact your local health department.

The best protection is the measles, mumps, and rubella (MMR) vaccine. Find out if you have been vaccinated for measles or have had measles previously. 

If you can’t locate your vaccination records, contact your doctor, school, previous doctors, or the Illinois Department of Public Health’s vaccination records portal, Vax Verify.

• If you have received two doses of the MMR vaccine, or were born before 1957, you are considered protected.
• People who are not fully vaccinated or unsure of their immunity should contact their doctor to report their potential exposure and call DCHD promptly to discuss any questions they might have. 
• Everyone should watch for symptomsof measles for 21 days after the potential exposure. Monitoring for symptoms is especially important for people who are not fully vaccinated or otherwise immune to measles.  Since breakthrough infections may occur, even exposed persons with immunity need to monitor for symptoms.
• If you notice symptoms of measles, such as fever, rash, cough, runny nose, and red and watery eyes, immediately isolate yourself by staying home. Contact your doctor right away. If you need to seek healthcare, call before going to your doctor’s office or the emergency room to notify them that you may have been exposed to measles. This call will help protect other patients and staff.  Also call DCHD at (630) 682-7400 for public health officials to support coordination and care. 

For additional information on measles:  https://illinois-doit-prod-idph.amsadobe.com/topics-services/diseases-and-conditions/measles.html