By: Ashmar Mandou

In an effort to combat the measles outbreak, the City of Chicago announced that everyone at the Halsted shelter should receive a second measles vaccine dose 28 days after the first dose. The policy aims to ensure the best protection for preschool children in particular until their immunity to measles is fully developed, and will prevent potential spread of the highly contagious virus to other preschool children that have not yet received a second dose of MMR. The City is asking families with children aged 1-5 years at the shelter to keep those children home from childcare and preschool until 21 days after they have received a second dose of the vaccine or 21 days after last exposure if the children cannot be vaccinated.

“While the MMR vaccine is the best protection against the virus, children are at highest risk for contracting breakthrough measles after receiving one dose of the vaccine, especially those less than 5 years old. We’re seeing some of these cases at the Halsted shelter, which isn’t surprising,” said CDPH Commissioner Olusimbo ‘Simbo’ Ige, MD, MPH. “I understand this will be a challenge for families, but we want to do everything to protect young children from contracting measles by ensuring 2 doses of the MMR vaccine.”  Recommendations from the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP) state that a second dose can be administered as soon as 28 days after the first. With the second dose of MMR, effectiveness increases to 97 percent. The State of Illinois requires two doses of MMR vaccine for K-12 school attendance; in response to this measles outbreak, this policy will be extended to children who are 5 years of age and younger. Shelter residents under 12 months who are not yet vaccinated must be excluded from daycare or early learning until 21 days after their last measles exposure.  The updated vaccination schedule for residents of the Pilsen shelter who are experiencing exposure to confirmed measles cases and are aged 1-5 will be as follows: 

• 1st dose 

• wait 28 days 

• 2nd dose 

• wait 21 days   
 
• Return to preschool or daycare 

To date, CDPH has identified 26 confirmed cases of measles in Chicago residents, the majority of which have been associated with Pilsen new arrivals shelter. Of the 26 confirmed cases, 19 are in children below the age of 5, underscoring the critical importance of the vaccine in fighting the spread of this disease in young children.