Chicago, Oct 1 (IANS): Chicago Public Schools (CPS), the third largest school district in the US, said that 1,101 students and 342 adults had contracted Covid-19 one month after it resumed in-person classes since the onset of the pandemic in March 2020.

The case numbers, for the period from August 29, reflected a change in the way CPS was reporting its data, Xinhua news agency reported on Friday citing the Chicago Tribune as saying.

CPS expanded the criteria to include all reported cases, not just cases its contact tracing team investigated and closed, the Chicago Tribune added.

Meanwhile, some 6,300 students and 280 adults were in quarantine or isolation as of Wednesday evening, according to CPS data.

By CPS definition in a classroom setting, a close contact is a student who was within 3 feet of an infected person for at least 15 minutes within a 24-hour period, with or without a mask.

Close contacts are directed to quarantine for 14 calendar days, unless they are fully vaccinated and asymptomatic.

But the vaccine is only available to people aged 12 years and older.

The district said it is expanding voluntary coronavirus testing program to all CPS schools by Friday.

The program is only mandatory for unvaccinated and half-vaccinated student-athletes during their sports seasons and unvaccinated staff members.

Nearly 31,000 people have registered for the program, and more than 14,000 nasal swabs have been administered through the program this school year, with 17 positive tests and more than 650 invalid results recorded, according to the CPS online Covid-19 reporting tool.

The district is also in the process of doubling the number of contact tracers.

The district has more than 30 contact tracers at present.

CPS, officially classified as City of Chicago School District for funding and districting reasons, had 340,658 students enrolled at start of school year 2020-2021.