One or two confirmed circumstances in a single classroom would require these courses to shut for 14 days, with all college students and employees members ordered to quarantine. The remainder of the varsity would proceed to function, but when two or extra individuals in several lecture rooms in the identical college examined constructive, the complete constructing would shut for an investigation, and won’t reopen for 2 weeks relying on the outcomes.

In California, the place colleges in two-thirds of the state have been barred from reopening in particular person for now, state tips name for a college to shut for not less than 14 days if greater than 5 p.c of its college students, school and employees check constructive over a two-week interval.

Chicago, the nation’s third-largest college district, has proposed a hybrid system for reopening that will put college students into 15-member pods that may be quarantined if one member checks constructive. Faculty buildings ought to shut if the town averages greater than 400 new circumstances every week or 200 circumstances a day, the plan states, with different worrying components like low hospital capability or a sudden spike in circumstances taken into consideration.

In Indiana, the place the center college pupil examined constructive on Thursday in Greenfield, an Indianapolis suburb of 23,000 individuals, the virus started to spike in mid-June, and the caseload has remained comparatively excessive. This week, Indianapolis opted to start out the varsity yr on-line.

The Greenfield-Central Group Faculty Company, with eight colleges and 4,400 college students, gave households the option of in-person or remote learning. At Greenfield Central Junior Excessive Faculty, which the scholar with the constructive check attends, about 15 p.c of the 700 enrolled college students opted for distant studying, mentioned Mr. Olin, the superintendent.

“It was overwhelming that our households wished us to return,” he mentioned, including that households wanted to be accountable and never ship college students to high school in the event that they have been displaying signs or awaiting check outcomes. College students are additionally required to put on masks besides when they’re consuming or for bodily training outdoors, he mentioned — and so far as he knew, the scholar who examined constructive was doing so.