A growing number of COVID-positive cases at Hopkinton High School could put in-person graduation in jeopardy and require mandatory pool testing for students in extracurricular activities, superintendent Carol Cavanaugh told School Committee members Thursday.

Twenty-one positive cases have been reported since Monday, according to material presented at the meeting. But Cavanaugh said that since that information had been prepared, school nurses have reported even more cases.

“The district may need to take bolder action,’’ she said. “Something absolutely has to be done.’’

These growing case numbers could lead to mandated pool testing for students who participate in spring sports or other extracurricular activities, she said.

Students who attend class but do not participate in extracurriculars cannot be mandated by law to do pool testing, Cavanaugh said.

Based on the timeline, these cases did not develop in school but are likely due to activity during the recent April vacation, she said.

“Our students have really let their guard down,’’ she said. They have been observed walking together, driving and socializing without wearing masks, she said.

“That socialization is leading to this enormous spread,’’ she said.

Cavanaugh said she is concerned that if this trend continues, “this is the kind of behavior that is going to preclude kids from being on the field for their graduation.’’

She said that would be a very disappointing occurrence, especially with everything that seniors have been through in the last year.

School Committee members are scheduled to take up the issue at their May 6 meeting.

Committee wants no action on pair of ATM articles

In other issues, the School Committee voted unanimously to ask voters to take no action on two school-related articles at Annual Town Meeting on May 8.

The committee originally had asked voters to move money out of stabilization and out of the Legacy Farms host community agreement to provide funding for potential enrollment increases. Enrollment figures in upcoming year are challenging to determine due to the pandemic, school officials have said.

The money no longer will be needed because the latest round of Elementary and Secondary School Emergency Relief funding should cover any unexpected needs, school finance director Susan Rothermich said.

Voters still will be asked to approve spending $1 million toward a feasibility study for a possible new Elmwood School. The district has been applying to the state for consideration of a new school to replace the current overcrowded building and was approved for consideration this year.

The money would come from the Legacy Farms host community agreement and would not directly impact taxpayers, Cavanaugh said. The project cannot move forward without voters approving a funding source, she said.

In other issues, the Select Board agreed to form a school building committee to study the potential Elmwood School project. The board briefly attended the Thursday meeting and voted to move the committee formation forward.

Quarantine guidance changes

In other issues, Cavanaugh reported that the state Department of Elementary and Secondary Education has changed guidance on quarantining after exposure to positive COVID-19 cases.

If an individual tests positive and other students or staff members were within 3-6 feet of that individual for at least 15 minutes while everyone involved was masked, they do not have to quarantine.

They still would be considered close contacts and would be notified. They must get tested, actively monitor for symptoms and follow key health and safety measures, Cavanaugh said.

This applies to close contacts only in classrooms or on the bus. Close contacts in other locations, such as athletics, lunch or out-of-school exposures, still would need to be quarantined, she said.