Of the 113 measles cases in the US so far, 83 have been part of outbreaks.
Of US measles cases, 59% weren't vaccinated and immunization status wasn't known for 24%.
Rashes appeared 11 to 13 days after routine MMR vaccination.
In all of 2023, US cases of the vaccine-preventable disease totaled 58.
Also, the CDC warned about declining MMR coverage in US kindergarteners, underscoring a need to boost vaccine confidence and access.
Ten of the city's cases--which include both adults and children--are linked to an outbreak at a migrant shelter.
Local health workers are offering the MMR vaccine at other shelters as well as at the city's landing zone.
Chicago health workers have vaccinated hundreds of shelter residents, as Arizona health officials investigate cases near Flagstaff.
Illinois and California are among 17 US jurisdictions that have reported measles cases this year.
The CDC said today that it has received reports of 45 cases from 17 jurisdictions so far this year.
