• Posted March 12, 2024

Measles Cases Climb to 4 at Chicago Migrant Shelter Outbreak

As the number of measles cases at a migrant shelter in Chicago climbed to four on Monday, a team from the U.S. Centers for Disease Control and Prevention has headed to that city to help contain the outbreak.

The Chicago Department of Public Health (CDPH) reported on Monday that two adults at the shelter had been diagnosed and were in stable condition. That followed a Sunday announcement that a school-aged child at the Pilsen migrant shelter had been hospitalized with measles, but was in “good condition.”

The first measles case detected at the shelter was a very young child who has since recovered and is no longer infectious.

The CDPH added Monday it has "assessed nearly all residents of the Pilsen shelter where there have been four confirmed measles cases, and successfully vaccinated more than 900 shelter residents with the measles-mumps-rubella (MMR) vaccine. More than 700 shelter residents who were assessed and found to already be immune from previous vaccination or infection were allowed to enter and exit the facility. Those who are newly vaccinated were instructed to remain at the shelter for 21 days from date of vaccination, which is when the vaccine confers full immunity."

“As long as measles circulates in Chicago, we will continue to take a proactive approach to protecting as many people as we can from this highly infectious disease,” CDPH Commissioner Dr. Olusimbo (Simbo) Ige, said in an agency news release. “Vaccination remains by far the most effective way to prevent the spread of measles. New arrivals and all Chicagoans should get the MMR vaccine if they haven't already.”

Importantly, if an unvaccinated person is exposed to measles and hasn't developed symptoms, an MMR vaccine can ward off infection if administered within 72 hours, the CDC says. A preventive injection called immune globulin can also be given within six days of exposure.

The child diagnosed Sunday attends Philip D. Armour Elementary School. The health department advised school-aged shelter residents not to attend school on Friday or Monday. 

“Once a student's vaccination status has been verified, students with confirmed vaccinations will be notified of the date to return to school,” Pedro Martinez, CEO of Chicago Public Schools (CPS), said in a letter sent to families on Monday.

Chicago's first measles case this year, announced just last Thursday, appears unrelated to the other four cases. That resident was not infectious as of last Wednesday, NBC News reported. 

Meanwhile, the CDC told the news outlet that a team of experts is expected to arrive in Chicago on Tuesday to support efforts to control the disease's spread.

Measles has spiked globally in recent months, and the United States has recorded at least 45 cases so far this year. In all of 2023, there were only 58 measles cases.

Why the increase? Vaccination rates in schools have declined nationwide. The share of U.S. kindergartners who had received both doses of the MMR vaccine was 93% in the 2022–23 school year, down from 94% in the 2020–21 year, NBC News reported.

To make matters worse, measles is highly contagious: An infected person can spread the virus to nearly 90% of people exposed to them if those people aren't immune, and infected people can remain contagious for roughly eight days.

Measles symptoms include a high fever, cough, pink eye and runny nose. Two to three days after symptoms start, people usually notice tiny white spots in their mouth. Between days three and five, a blotchy rash often develops from head to toe, according to the CDC.

Roughly 1 to 3 out of every 1,000 children infected with measles die from respiratory and neurological complications. In rare cases, measles can lead to blindness or long-term vision problems. 

More information

Visit the U.S. Centers for Disease Control and Prevention for more on measles.

SOURCE: Chicago Department of Public Health, news release, March 11, 2024; NBC News