Health experts concerned that falling measles vaccination rates in Illinois and Chicago area schools may be putting students at risk
CHICAGO (CBS) – Cook County recorded at least four measles cases last year, the first since 2019.
Health officials say this is concerning -- because at the same time, more schools are falling below the federal threshold for herd immunity.
The Centers for Disease Control and Prevention (CDC) sets 95% as the target level to achieve herd immunity. That is the percentage of vaccinated students necessary per school to protect those who aren't immunized from getting the disease.
"Measles is a nasty, nasty virus, and there's not much we can do after you've had it, so we really need to prevent people from getting it," said Dr. Taylor Heald-Sargent, an infectious disease specialist at Lurie Children's Hospital.
A CBS 2 analysis of data from the Illinois State Board of Education (ISBE) and the Chicago Public Schools (CPS) shows more schools dropping below that 95% level in recent years.
"What we know is that there's been a slight increase in the number of exemptions, that is parents that say, 'I don't want my kid to have it for religious, philosophical, or medical reason,'" said Dr. LaMar Hasbrouck, the Cook County Department of Public Health Chief Operating Officer, "and obviously, that's going to increase exposure for some kids to be vulnerable to measles."
The numbers
CBS 2 looked at the percentage of students protected against measles from the 2019-2020 school year through the 2022-2023 school year for the state, and through the current 2023-2024 school year for CPS. Statewide numbers for this school year won't be available until March.
Statewide, the number of schools under-vaccinated increased from 497 in 2019 to 882 by the start of the 2022 school year. That is a 77% increase.
In the 10-county Chicago metro area, the number of schools below the 95% threshold increased from 235 to 358 in those four school years. That is 52% more schools where students are at risk.
"Obviously, the lower the protection, the more the vulnerability -- which means not only do you have more students that are vulnerable, but it means that should a student get measles, that can basically run through that community very quickly," said Dr. Hasbrouck.
And, finally among CPS schools, the increase is even more dramatic. 157% more schools fell below 95% for the 2022-23 school year. 288 schools compared to 112 in 2019. And, since CPS has data for this current school year, we know the number of schools with lower protection levels has jumped to more than 500, that's a 367% increase over five school years ago.
"I was shocked looking at the numbers recently that there are schools well below the herd immunity level of 95%," said Dr. Heald-Sargent.
Is the migrant crisis affecting vaccination rates in CPS schools?
The district did not answer that question specifically but said it complies with the McKinney-Vento Act which requires the immediate enrollment of students experiencing homelessness, even if medical or other records cannot be produced at the time of enrollment.
A district spokesperson added that student health and safety is a top priority.
CPS Full Statement:
Chicago Public Schools (CPS) continues to make the health and safety of our students and staff our top priority while ensuring that students are provided with rigorous academic programming.
The best way to support academic success is to minimize time away from school whenever possible. To help students stay healthy, safe and in school, the District continues to supplement access to care through a variety of sources, including partner-managed School Based Health Centers, weekly CPS-managed vaccination events, and in various collaborations with Chicago Department of Public Health (CDPH).
Every health and safety measure CPS has implemented has been in accordance with the guidance of the CDPH, the Illinois Department of Public Health and the Centers for Disease Control (CDC), and we will continue to work with our public health partners to provide an appropriate response to future health challenges.
