UPDATE 05/01/25: On April 30, Chicago Department of Public Health (CDPH) notified the public of a measles exposure at Chicago Public Library, Independence Branch, on April 21, 2025. Upon further investigation, CDPH has determined that the patient did not visit the library on this day. Independence Branch is no longer considered a measles exposure location. No additional action needs to be taken by staff or patrons who were present at Independence Branch on April 21 at this time.

CHICAGO - The Chicago Department of Public Health and Cook County Department of Public Health have identified two confirmed cases of measles. These are the first two cases in Cook County in 2025.

One case was identified as an adult who is a suburban Cook County resident, and whose vaccination status is unknown. They presented to a local Hospital for medical care on Monday, April 28 and was quickly isolated.

Another case was identified in an adult Chicago resident who traveled internationally through O'Hare Airport in early April. The individual had 1 prior dose of MMR vaccine. This patient had rash onset on April 25 and has been isolated at home since being diagnosed.

All persons 12 months of age or older who plan to travel internationally should ensure that they have received 2 doses of MMR at least 2 weeks prior to travel, or other evidence of immunity.

The health departments are working together collaboratively to identify and notify people who may have been exposed. The Cook County Department of Public Health is investigating the Suburban Cook County case, and the City of Chicago Department of Public Health is investigating the Chicago case.

The following locations are points of potential public exposure:

• Monday 4/21/2025: Chicago Public Library – Independence Branch, 4024 N. Elston Ave.
• Monday 4/21/2025: Fittingly Delicious, 3939 W. Irving Park Rd.
• Tuesday 4/22/2025: O'Hare Airport, 10 am–8 pm, especially Terminal 1
• Wednesday 4/23/2025: O'Hare Airport, 10 am–8 pm, especially Terminal 1
• Friday 4/25/2025: Aldi: 7235 39th St, Lyons, IL 6053, 10 am–12:30 pm.
• Sunday 4/27/2025: Shell: 3901 S. Harlem Ave., Stickney, IL 60402, 10 am–12:30 pm.
• Monday 4/28/2025: Mobil: 2945 S. Harlem Ave, Berwyn, IL 60402, 10:20 am–1 pm.

For Individuals Who May Have Been Exposed:

Individuals who may have been exposed should notify their healthcare provider if they are unsure about prior vaccination. The healthcare provider will determine the need for testing if symptoms develop.

If an exposed individual develops symptoms, they should notify their healthcare provider or a healthcare facility before going to a medical office or emergency department for evaluation to ensure that special arrangements can be made to prevent other patients and medical staff from possible exposure.

Exposed individuals that are unvaccinated against measles, mumps, and rubella (MMR) should talk with their doctor about getting MMR vaccine. It is not harmful to get MMR vaccine after being exposed to measles, mumps, or rubella, and doing so may prevent severe measles if given early enough after exposure.

Most individuals are vaccinated against measles routinely in childhood and are not at high risk. The best defense against measles is vaccination. Two doses of MMR vaccine are 97% effective against measles and generally provide lifelong immunity.

• The first dose should be given between 12-15 months of age
• The second between the ages of 4-6 years old.

"As public health officials around the state continue to work diligently to guard against further spread of measles, we are reminded again that being fully immunized remains the best and most effective way for everyone to protect themselves and those they love," said IDPH Director Dr. Sameer Vohra. "The MMR vaccine is safe and effective. We encourage anyone who is unvaccinated, or under-vaccinated, to speak with their medical provider and take appropriate steps to get up to date on the recommended shots."

"We are experiencing a resurgence of measles in the United States, despite the fact that two doses of the MMR vaccine can prevent it. Misinformation has contributed to declining vaccination rates and fueled recent outbreaks. The MMR vaccine has been in use for over 50 years, is highly effective, and has protected millions of lives,” said Interim CCDPH Chief Operating Officer Dr. Kiran Joshi.

“Chicago is no stranger to measles after our outbreak last spring and having contained it once we know we can do it again,” said Dr. Olusimbo Ige, CDPH Commissioner. “The MMR vaccine is an extremely effective tool for combatting illness and saving lives in our community, it's never too late to get vaccinated and protect yourself from measles.”

About Measles - Measles is a highly contagious respiratory disease that spreads easily through the air when an infected person breathes, coughs or sneezes. Measles is so contagious that if one person has it, 90 percent of the people close to that person who are not immune will also become infected with the measles virus. Complications from measles can lead to pneumonia, seizures, hearing loss, life-long brain damage and death.

The virus can linger in a room for up to two hours and can be especially dangerous for babies and young children, pregnant women, and people with compromised immune systems.

Measles Symptoms - Measles symptoms appear up to 21 days following exposure. Symptoms of measles include rash, high fever, cough, runny nose, and red, watery eyes. The rash usually begins on the face and spreads to the trunk. A person is generally contagious the four days before and four days after the onset of a rash.

Where to Get Vaccinated - To make an appointment for measles vaccination at a Cook County Health community health center in Chicago or suburban Cook County call 833-308-1988.

Unvaccinated individuals who do not have a healthcare provider are encouraged to contact Cook County Health at 833-308-1988 to schedule a vaccination appointment.

Chicago Department of Public Health (CDPH) offers free MMR vaccinations for anyone who needs them, regardless of insurance status, at CDPH Immunization Clinics throughout the city. Walk-ins are welcome, but registration is highly encouraged. Create an account and register for an appointment at getvaxchi.chicago.gov or by calling the clinic. Get the Facts about measles on the CDPH website.

Check Your Vaccination History - The CDC recommends two doses of the MMR vaccine for lifelong protection. If unsure, you can check your vaccine history. Immunization records recorded in the Illinois immunization registry can be accessed using the Illinois Department of Public Health Vax Verify portal.

Consider Your Age & Timing - If you were vaccinated before 1968, check with your healthcare provider about a revaccination. A blood test can confirm if you still have immunity. Talk to your healthcare provider if you're unsure.

Assess Exposure & Risk - If you got just one dose, have a weakened immune system, or have been exposed to an outbreak, consult a healthcare provider about immunization.

Protect Yourself from Misinformation - Vitamin A is not a substitute for vaccination. Vitamin A supplementation does not prevent measles infection. It can help reduce the severity of measles symptoms—particularly in malnourished children or those with vitamin A deficiency—but only after infection has occurred. According to the CDC, vitamin A may be used as part of supportive care for measles in some patients, under medical supervision. However, relying on vitamin A instead of vaccination puts individuals and communities at risk of serious infections and disease spread.

Traveling Out of the Country - Individuals who are traveling out of the country, including children over the age of 6 months, should talk to their healthcare provider about whether an additional dose of MMR vaccine is recommended before travel.

People who are frequently around international travelers, such as individuals who work at airports or taxi and rideshare drivers, should also be sure to double check their vaccination status, as their risk of exposure to measles is heightened.

To learn more about Measles and download fact sheets in multiple languages visit Measles - Cook County Department of Public Health or learn more on the CDC website.

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