With 53 cases of measles recorded in the city and suburbs, when does it peak?

Measles cases in Illinois stand at 53, the Chicago Department of Public Health reports. Many of those falling sick are children age 4 and younger.
Associated Press file

Measles infections related to an outbreak at a Chicago migrant shelter have proliferated from one case reported on March 4 to 53 as of Monday statewide.

Nearly 60% of those falling sick are children age 4 and younger, Chicago Department of Public Health records show. Three cases were reported in suburban Cook, Lake and Will counties; the rest involve Chicago residents.

Individuals who have had measles or have been vaccinated are protected but the spike shows how contagious the respiratory virus can be.

At what point will Illinois hit its measles peak?

It’s difficult to say, said Dr. LaMar Hasbrouck, Cook County Department of Public Health chief operating officer.

Chicago’s department of public health has vaccinated more than 5,000 new arrivals and “as vaccinations go up, herd immunity goes up and then the likelihood of new infections goes down,” Hasbrouck noted.

“Thankfully, there hasn’t been a new infection for the last four days. But we really can’t predict where it’s going to go at this point.”

Asked if infections will top the current count, Hasbrouck said, “if I had to predict … I don’t think we’ll stop at 53. And, we’ll probably see more of what I’m going to call ‘imported cases’ into other surrounding collar counties as migrants begin to move out and settle into communities.”

The Lake County Health Department has not had any additional cases of measles since March 23, communications manager Emily Young said.

DuPage County Health Department spokeswoman Cailyn Eckelberry said the agency has “received several reports of suspect cases, though, to date, none have tested positive and met case criteria for measles. Our public health investigations and response continue.”

Public health experts are urging residents to check their vaccination status and get inoculated against the disease, which has a 90% “attack rate.”

For example, the virus can circulate in a room for up to two hours after an infected person sneezes or coughs. The infection rate is about 90% for those who aren’t protected.

The U.S. introduced a measles vaccination program in 1963 which almost eliminated the disease. Now, public health departments are educating and re-educating medical professionals to watch for symptoms of measles that include a cough, rash, fever and runny eyes, Hasbrouck noted.

“We want to make sure everyone has measles as top of mind.”

Young children are more vulnerable to measles as infants don’t receive their first measles shot until 12 months.

Illinois Department of Public Health data dating back to 2010 shows the most measles cases before 2024 were 17 in 2015 after an outbreak at a Palatine day care center.

The Chicago region is handling an influx of migrant families and individuals, many from Central and South America, who are seeking asylum. Over 38,000 migrants have been sent to Illinois from Texas since summer 2022, according to Gov. J.B. Pritzker’s office.