A second case of Covid-19 has been confirmed in an individual at the Tisbury school and a first case has been confirmed in the Edgartown school, Martha’s Vineyard schools superintendent Matt D’Andrea wrote in a pair of letters that went out to parents on Sunday and Monday evening.

The two new cases in the Island elementary schools come after a Tisbury school student tested positive on Friday, making a trio of positive cases in the public school system over the past three days.

Tisbury health agent Maura Valley confirmed that the first individual who tested positive was a student at the Tisbury school who had spent all of last week in quarantine after a close contact tested positive for the virus. Ms. Valley said the individual had no known contacts connected to the school, and that the student had not been in the school building since last week.

But in a letter that went out to parents Sunday night, Mr. D'Andrea said that a second individual at the Tisbury school had tested positive for the virus. And at an up-Island school committee meeting Monday evening, Mr. D'Andrea said that there had also been a confirmed case in the Edgartown school. A subsequent letter went out to parents around 6 p.m. Monday evening confirming the third case. 

Neither letter specified whether the individuals who tested positive were students, faculty members or connected to the school in a different capacity. Ms. Valley previously confirmed on Friday that the first Tisbury school case was a student. 

The letters also did not specify whether the individuals were contacts with the Tisbury school student who previously tested positive for the virus on Friday.

“For confidentiality purposes we cannot disclose the identity of the individual,” Mr. D’Andrea wrote in the letter Sunday evening to Tisbury parents. “We are confident that in both cases transmission has occurred outside of school. All close contacts have been notified.”

The Edgartown letter contained similar language regarding confidentiality. 

Mr. D’Andrea was not immediately available for comment Monday afternoon.

At an up-Island school committee meeting Monday night, Mr. D'Andrea said that based on preliminary inquiry, it appeared the recent positive cases were not spread in the school, but contracted from external sources outside of the school building.

“What we were learning at this time is that they’re not school-based spread. The students who have contracted the virus have done it outside of school,” he said.

The two individuals to test positive at the Tisbury School and the third who tested positive at the Edgartown school mark the first positive cases in the Martha’s Vineyard kindergarten through grade 12 public school district. Last Thursday, a positive case was reported at the Vineyard Haven branch of Project Headway — a preschool program that is operated under the Island public school system umbrella, making four positive cases overall. 

The news comes as the schools continue to move forward with their re-opening plans, which have been slowly rolled out since the beginning of the school year. As of Monday, students in kindergarten through fifth grade have already returned to in-person learning on a regular basis, with students back for full five-day weeks in certain districts. On Monday, Mr. D’Andrea said middle schools across the Island were preparing to welcome students back more regularly beginning Monday November 16.

Mr. D’Andrea praised teachers and school families for complying with safety regulations so far, stressing the importance of continuing to enforce health and safety measures.

“The safety measures that we have in place in our schools, the masking, social distancing, the hand-washing, the self checks everyday, they are effective,” said Mr. D’Andrea. “Not only from what I see on the Island but also across the state, there is a lower incidence of spread in schools than outside of schools, and that's because of those safety measures.”

According to Mr. D’Andrea, the schools are closely monitoring the cases and does not expect to roll back any re-opening plans at the moment.

“We'll continue to work with our health and safety committee to watch as things unfold, but we still want to make sure that we do what's best for our students not only health-wise but education-wise,” he said.

The new positive cases also comes as the hospital has reported a spike in Island coronavirus cases over the weekend, with 20 new patients and a case cluster occurring among employees of Cronig’s Market.

Public schools in the state have to follow extensive coronavirus guidelines when an individual connected to the school tests positive for the virus. The Department of Elementary and Secondary Education requires the building to be completely disinfected and closed for at least 12 hours after the last time the Covid-19 positive individual was in the building, as well as a host of other contact-tracing requirements.

The Tisbury School did not need to be closed Friday because the Covid-positive individual had not been in the building for nearly a week. It was not immediately clear whether further steps would have to be taken considering the second positive case.

In his letter, Mr. D’Andrea urged parents to exhibit caution and to closely watch their children for illness.

“Please continue to monitor your child for any symptoms of COVID-19 and complete the daily checklist prior to arriving at school in the morning,” Mr. D’Andrea wrote. “If your child is experiencing any COVID-19 symptoms, please keep him/her home and contact your primary care physician. The district will continue to follow the school-based safety measures as outlined by the CDC and the Massachusetts Department of Public Health.”

“Please do not hesitate to contact me if you have any questions,” he added.

Updated to include information regarding the positive case reported in the Edgartown school. Maia Coleman contributed reporting.