Illinois reports 2 cases of measles in Cook County, prompting health alert

CHICAGO, Ill. (WTVO) — Two cases of measles have been confirmed in Cook County, according to health officials.

Authorities said a Cook County resident went to a hospital on Monday, April 28th, and was quickly isolated. Another individual was quarantined after traveling through O’Hare airport in early April.

According to the Illinois Department of Public Health, there are three confirmed cases in Illinois so far.

Most people are vaccinated against measles in childhood.

According to IDPH, 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

“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,” the IDPH said.

“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.”

According to the Centers for Disease Control and Prevention, more than 800 measles cases have been confirmed in 2025.

As new cases pop up every week, at least 10 official outbreaks have occurred, according to the CDC. An outbreak is defined as three or more cases of measles that are related.

The largest known outbreak is in West Texas, where the case count nears 600, according to local health officials.

Last year, a measles outbreak was reported at a Chicago migrant shelter, prompting a response from the CDC, and subsequently spread to the suburbs.

If the spread of measles continues as it has been, the U.S. risks losing its “measles elimination status,” a designation the country has had for 25 years.

The CDC reports 96% of cases so far have been in people who are unvaccinated or whose vaccination status is unknown. The majority of those sickened have also been children.