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CHICAGO - Another measles case was detected in Chicago this week, bringing the city’s outbreak total to 63 – far beyond the yearly average.
The most recent case, a girl between 5 and 17 years old, was reported Tuesday to the Chicago Department of Public Health, but it wasn’t known where she contracted the highly contagious disease, officials said.
A migrant shelter in the Pilsen neighborhood was previously linked to the majority of measles cases when the outbreak began in early March. Those were among the first measles cases reported in Chicago since 2019. About half the cases in Chicago have been in children younger than 5.
Two additional cases of measles have been detected in suburban Cook County in recent weeks, according to the county health department, which said Thursday that a south suburban grocery store was identified as a possible exposure location.
Anyone who visited the Sam’s Club, 9400 S. Western Ave., in Evergreen Park between 10 a.m. and 2:45 p.m. April 9 could have contracted measles from a person who was contagious with the disease, the Cook County Department of Public Health said. The person there who was confirmed to have measles is a Chicago resident, but their case was not linked to any city migrant shelter.
The Chicago-area outbreak has accounted for the majority of measles cases this year in the U.S. With another four cases detected in DuPage, Lake and Will Counties, the state’s total case count is 69 — making up more than half of the 121 cases reported nationwide by the U.S. Centers for Disease Control and Prevention.
Dr. Alfredo Mena Lora, director of infectious diseases at Saint Anthony Hospital in Little Village, said Chicago is experiencing a "unique situation" with the outbreak given its high vaccination rate against measles.
Chicago Public Health Commissioner Olusimbo Ige has previously said "new arrivals didn’t bring measles to Chicago," but she and Mena Lora say migrants are among the most vulnerable to the disease because of low vaccination rates in the countries they are from, and their crowded living situations at city shelters.
"If you were to look at any other environment — let’s say a place where there’s less cold weather, or more of a sprawl or rather less congregated, that one case would not have spread as easily to the other cases which then spread to other cases and other cases and other cases," Mena Lora said.
Last year, the Illinois Department of Public Health reported five measles cases, none of which were in Chicago. Zero cases were reported in the state during the three years before then. The last time Illinois had double-digit measles cases was 2015, with 17 infections.
Mena Lora said he’s "confident" the current outbreak will be contained as he credited Chicago health officials with quickly isolating those who contract measles, as well as their efficiency in administering tests and vaccines.
City health officials have said the outbreak has significantly subsided in recent weeks. Infections had steadily increased until spiking at 36 new cases reported within a week in late March. Since then, 10 cases have been detected in the city.
More than 15,000 doses of the measles vaccine have been administered in Chicago since the outbreak started March 7, the city health department said. The majority of those doses were given to migrants staying in shelters.
"Our tools for measles are pretty strong," Mena Lora said. "This vaccine is very potent. It’s a two-dose vaccine: at one dose, it’s about 90% effective, and then it bumps up above 95% with your second dose."
Measles symptoms generally appear 10 to 14 days after exposure. Common symptoms include fever, cough, runny nose and red or watery eyes, according to the CDC. A rash can appear three to five days after initial symptoms begin.
Health officials say families with children ages 1 to 5 should keep them home until 21 days after receiving the second dose of the vaccine, or 21 days after last exposure if they cannot be vaccinated.