Illinois schools are not COVID-19 superspreaders, data shows

In all, there were 16 schools statewide in the past month that were identified as having experienced an outbreak of the coronavirus, according to state records. “It’s safe to keep schools open,” said Dr. Daniel Johnson of University of Chicago Medical Center.

SHARE Illinois schools are not COVID-19 superspreaders, data shows

One of 16 outbreaks tied to Illinois schools this fall was at Yeshivas Tiferes Tzvi Academy at 6317 N. California Ave. in West Rogers Park.

Ashlee Rezin Garcia/Sun-Times

Even as the region enters its worst period of the pandemic thus far, the vast majority of public and private schools in the Chicago area that have reopened in some capacity this fall have had little confirmed exposure to the coronavirus in the past month, according to a Chicago Sun-Times analysis of state data.

A small fraction of schools have had outbreaks where virus transmission has been traced to school buildings, while high schools have shown to be more likely to experience COVID-19 scares than elementary schools, records show.

Those findings match nationwide figures showing relatively low instances of significant spread in educational settings, especially among younger students, and provide some insight into why health officials nationally and in Chicago have expressed strong confidence that schools are safer to reopen than first thought, even as the pandemic rages on.

The difference between elementary and high school infections also partially explains why Chicago Public Schools has prioritized the return of its youngest students as the district makes its third attempt in January to open its classrooms for the first time since March.

“It’s safe to keep schools open,” said Dr. Daniel Johnson, chief of Pediatric Infectious Diseases at the University of Chicago Medical Center. Johnson said evidence has shown minimal spread of the virus in school buildings even as transmission rises in the surrounding community.

The data reviewed by the Sun-Times, first released early last month by the Illinois Department of Public Health and most recently updated through the end of November, for the first time included contact-traced infections in schools. The department had previously only released school-aged cases that were not tied to specific facilities.

In all, there were 16 schools statewide in the past month — including six in the suburbs and two in Chicago — that were identified as having experienced an outbreak of COVID-19. IDPH defines school outbreaks as having five confirmed infections in people who are from different households and may have a shared exposure on school grounds, including during before- and after-school programs. Of those 16 schools, which serve a combined less than 9,000 students, two saw a cluster of between 11 and 16 connected cases and the rest had less than 10.

While the state hasn’t tracked how many private school students have returned for in-person learning in any form during the fall semester, about 39 percent of the state’s 1.9 million public school students, more than 750,000, are currently in either part- or full-time in-person learning.

Separately, 482 public and private schools, about a quarter of all schools in the six-county Chicago area — Cook, DuPage, Kane, Lake, McHenry and Will — have recorded at least some exposure to the virus, state data shows. These exposures mean an infected person was in the building during their 14-day contagious period; they were not found to have contracted or transmitted the virus at the school.

About 89% of those schools, 428, have had fewer than five exposures in the past month, another 31 schools have had between five to 10 exposures and only eight schools have experienced more than 10. Of the 41 schools with five or more exposures, 24 were high schools.


There was an outbreak of COVID-19 at St. Mary Immaculate Parish School in suburban Plainfield this fall, state data shows.

Rich Hein/Sun-Times

Plainfield outbreak

One of those two larger outbreaks happened at St. Mary Immaculate Parish School in suburban Plainfield, and the other was Blessed Sacrament School in downstate Quincy. The two Chicago schools to have traceable outbreaks were Jewish private schools, Yeshiva Tiferes Tzvi and Hanna Sacks Bais Yaakov High School, both in West Ridge.

Yeshiva Tiferes Tzvi is still open for in-person instruction. A letter sent to parents last month said four full classes are in quarantine along with portions of another four. That has left more than 100 students and more than 20 staff members temporarily out of school, accounting for almost 10% of the people usually in the building. While only five to 10 cases were suspected to have been transmitted in the school, the letter said there are 30 cases in all at Yeshiva Tiferes Tzvi. School officials could not be reached for comment.

There also appear to be some faults with the data provided by IDPH. At Hinsdale Central and Hinsdale South high schools, there were a combined 25 active cases among students and employees as of Nov. 25, a district tracker showed. State data reported each school having less than five exposures in the past month. IDPH acknowledged that the completeness of its dataset is affected by several factors.

Nonetheless, evidence shows it’s highly unlikely that any additional cases would have been contracted at school, said Dr. Susan Bleasdale, medical director of infection prevention and control at the University of Illinois at Chicago.

“Schools themselves and the activities associated with schools are not the source of transmission,” Bleasdale said. She went so far as to suggest the outbreaks in particular might look worse in the data than in reality because it’s hard to prove transmission happened in the schools. A cluster could develop among friends who gather at a home in the evening and don’t wear masks, for example, but be falsely attributed to the school because those friends have classes together. Those incidents can happen whether schools are open or not.

Bleasdale said schools sometimes appear to have an increase in cases only because teachers and students are contracting the virus outside of schools and then are identified as having been in the building.

‘You can operate schools safely’

Dr. Johnson, the University of Chicago pediatric infectious diseases chief, said chances of in-school transmission are very low no matter the level of community spread because of layered mitigation protocols at schools. When one piece fails, like a student taking off a mask for a few minutes, there’s still social distancing, ventilation, hygiene and smaller class pods for protection, he said.

“If you institute those and actually follow those mitigation steps, then you can operate schools safely, and that’s what datasets have shown,” Johnson said. “The proof is in the pudding. What we’ve seen is that yes, in most school settings, students, just like teachers, follow the rules.”

In instances when schools reopened this fall only to go back to remote learning weeks later, those closures generally did not have to do with confirmed in-school transmission through contact tracing, the Sun-Times found.

Announcing closures at Lincoln-Way Community High School District 210, Supt. R. Scott Tingley wrote in a Nov. 9 letter to families that “at this point, there has been little to no evidence of transmission during the school day. The majority of cases have been traced to social gatherings and/or family settings.”

Tingley said the district was returning to remote learning because about 600 students at Lincoln-Way’s three high schools were in quarantine after several students’ close contacts tested positive, making it nearly impossible to effectively continue holding classes with only a fraction able to attend. Despite so many quarantined, the risk of in-school transmission would not have increased and there was no new evidence of in-school spread, experts said. There were nine active cases in the district Thursday.

Two days later, Supt. Stephanie Palmer at District 80 in Norridge said the school system had to close because of a staffing shortage and because students were coming to school when a family member was sick, forcing their peers to quarantine. “Our partnership with our community is not working,” she wrote.

District 200 officials in Wheaton told families when announcing renewed closures last month that “while we are confident the virus is not being transmitted within our schools, we are also aware that our school-based mitigation efforts are not being replicated outside of school, and that has resulted in creating unsustainable learning models in grades 6–12.”

Expert: transparency key

Johnson said transparency surrounding school reopening is important so anxious teachers and families can understand what the evidence shows.

It appears there’s work to be done on that end. In an earlier CPS survey, less than a third of parents of preschoolers and children with complex special needs said they would send their kids back to schools. New York City’s public schools system has been open to in-person learning for much of the fall and will reopen next week after a short closure, but a majority of students have opted to continue learning remotely.

CPS families have until Monday to make a final decision on whether they plan to send their children back to school in the new year. Preschoolers and special education cluster programs are due back Jan. 11, and all other K-8 students will return Feb. 1, CPS said.

Contributing: Madeline Kenney

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