On April 30, the Chicago Department of Public Health, in conjunction with the Cook County Department of Public Health, confirmed two cases of measles within Cook County. These incidents mark the first occurrences of measles in Cook County, Illinois, for the current year. One of the cases involves an adult resident of suburban Cook County, whose vaccination history remains unclear. The second case pertains to an adult resident of Chicago who had traveled internationally via O’Hare Airport in early April. This individual, who had received one prior dose of the measles vaccine, developed a rash that began on April 25 and has since been in isolation at home following the diagnosis.
