Northwood School in Lake Placid (Enterprise photo — Andy Flynn)

LAKE PLACID — Lake Placid’s Northwood School is sending students home in an effort to halt any further spread of the coronavirus, and in hopes that its seniors may be able to return at the end of the month for prom and commencement.

Altogether, 24 people at the private boarding school have tested positive for COVID-19 in recent weeks.

This cluster of cases was first discovered in late April after a student on the boys soccer team started experiencing symptoms of COVID-19, according to Northwood Assistant Head of School Life John Spear. That student ultimately tested positive, and subsequent testing of other students on the soccer team revealed more positives.

More students were tested last week and additional positives were found among the boys soccer, boys hockey and girls hockey teams. Another round of school-wide COVID-19 testing this week revealed two new positives, one in the boys’ soccer cohort and another in the independent boys’ cohort, according to Spear.

That brings the total number of positive cases among the school community to 24: two staff members and 22 students. None of them are isolating on campus, according to Spear. Students are either isolating at an off-campus location or out of state.

The Essex County Health Department has ordered an additional 57 people — including students and staff — to quarantine as a precaution after they had close contact with people who tested positive.

Throughout the school year, students have been separated into small groups, or “cohorts,” in an effort to cut down on the risk of widespread coronavirus exposure if a student were to test positive. With the additional cases found this week, positives have been discovered in three of five student cohorts, according to Spear.

Spear said this discovery was concerning enough to lead to the school’s decision to send its students home to complete the school year remotely.

“Our top priority is the health and safety of our students,” Spear said Thursday. “We are, right now, 16 days away from commencement. Another top priority is preserving that for our seniors.”

The school plans to welcome back only its seniors for prom on May 21 and for graduation on May 22. Fully vaccinated people will be able to come to the event as guests or participants without getting tested, but those who are not fully vaccinated will be required to test negative first, according to Spear.

“We will have the capacity to test people on site if they arrive without a test,” he said.

A few students will be allowed to stay on campus until May 22, either because they’re from other countries and wouldn’t be able to return in time for graduation if they left, or for other personal reasons.

The school can’t say for sure how or where the first student to test positive was exposed to the coronavirus, according to Spear.

“We know the student and all of his teammates were out of state at a soccer tournament the week before they returned to Northwood,” he said. “It’s possible that student, and maybe others, contracted COVID at that tournament or while en route back to Lake Placid.”

Every student returning to school after the tournament had to test negative first, per the school’s policy. They all took a PCR test 18 hours before traveling back home and received negative results, according to Spear. All of the students in the boys soccer cohort were tested again three days later, and each tested negative again. It was five days after that last test result that one of the students went to the school’s health center because he was experiencing symptoms of COVID-19.

Most of Northwood School’s teachers and staff have been vaccinated, and many of the students who are eligible have been as well, Northwood School Marketing Director Darcy Norfolk said earlier this week. The school hosted a vaccine clinic late last month; however, those under the age of 16 aren’t eligible to get vaccinated yet, and some eligible students were away from school when the clinic happened.