By CBS 2 Chicago Staff

CHICAGO (CBS) — Starting Friday, businesses in suburban Cook County are being urged to require customers to show proof they’ve been vaccinated before walking in the door.

Customers can also show a negative COVID test to get in, as long as it was taken in the past 24 hours. CBS 2 Political Investigator Dana Kozlov report,  a suburban school district is at the center of this new CDC advice.

READ MORE: Chicago Weather Alert: Lake-Effect Snow On The Way With 6 To 8 Inches Possible In Some Areas; Winter Storm Warning Issued

It started in August and 90 of Lake County’s public schools participated. All call it a success. But it may not be possible for every school to execute, without help.

North Shore School District 112 jumped at the chance to participate in Lake County’s “Test to Stay” program at the start of the school year. Superintendent Michael Lubelfeld called it a game changer.

“It’s affected more than 100 student so far, in a good way, this year,” Lubelfeld said.

More than 100 students, in nine of District 112’s schools,  that were able to stay in the classroom. That’s instead of staying home to quarantine after close contact with someone with COVID-19.

“This has been extremely effective.”

That’s according to Mark Pfister, the Executive Director of Lake County’s Health Department who said county-wide, the program saved 8,152 in-person learning days. The pilot program they developed used Abbott Labs’ BinaxNow kits to test unvaccinated, asymptomatic exposed students in school, several times over the course of a week.

READ MORE: Two Men Shot Dead In Car In Ravenswood; Car Goes On To Crash And Catch Fire

“So the nurses are actually doing the testing. Days one, three, five and seven and they’re also identifying who are the potential contacts in the classroom,” Pfister said, who added that only 1.5% of those exposed students and staff got COVID.

The Centers for Disease Control and Prevention just published Lake County’s research paper on its website and is now supporting the “test to stay” program as a nationwide option.  But the CDC acknowledges the testing program requires money and resources, like nurses,  which can keep  less affluent districts from implementing the program.

“That was actually part of our research article. To assist schools with low resources so they can do this,” Pfister said.

In November, Chicago Public Schools announced it was implementing a “test to stay” program in some of its schools. Unlike Lake County schools, CPS does not have a nurse in every school.

“I think the federal government and the state government should be funding all of the costs associated with pandemic management,” Lubelfeld said.

MORE NEWS: Pair Charged In Murder Of 8-Year-Old Melissa Ortega Denied Bail; Accused Teen Gunman Committed Three Previous Carjackings, Prosecutors Say

In Lake County 145 schools are now participating in the program. CBS 2 reached out to CPS asking for information about its pilot program.

CBS 2 Chicago Staff