A coronavirus case cluster that has contributed to an overall spike in Covid-19 patients on Island this week continues to expand, with Island boards of health and the Martha’s Vineyard Hospital reporting a combined four new cases Thursday.

An earlier report stated that there had been five new cases Thursday, including a patient who tested positive off-Island. Health agents later corrected that number to four.

"Through contact tracing we learned that the individual tested off-island is no longer an Island resident and has not lived on the Island for several months," Tisbury health agent Maura Valley wrote in an email. "The report has been revised to remove this individual from the positive case count."

One of the new patients is connected to a case cluster that health agents identified earlier this week, Ms. Valley confirmed. The cluster stemmed from a wedding held on the Island over Columbus Day weekend. There have now been 10 patients to test positive who were connected to the wedding, eight of whom remain on Island, and at least six of whom are in isolation.

The new positive patient connected to the wedding cluster is a contact of a wedding guest, but did not attend the actual event, Ms. Valley said. This is the first individual connected to the wedding who tested positive but did not attend the event.

“The individual is a contact of one of the wedding positives,” Ms. Valley said. “It wasn’t some kind of incidental contact with the event.”

Three of the new patients Thursday, including the individual connected to the cluster, were reported by the Martha’s Vineyard Hospital. In a phone interview, Ms. Valley confirmed that the boards of health had learned of one additional patient who had tested positive at TestMV. 

The four total new cases on Thursday add to a week that has already seen the highest number of virus cases on-Island since the pandemic began. Two new patients were reported Friday, six on Monday, three Wednesday and now four on Thursday, making 15 in the last seven days and 13 since the weekend.

Seven of the patients have tested positive at the Martha’s Vineyard Hospital. Eight others have tested positive at TestMV. 

The hospital tests symptomatic patients and their close contacts for the virus, while TestMV is a free, comprehensive testing site focused on asymptomatic patients.

In the hospital’s daily Covid-19 update, which is accurate as of 9 a.m. Thursday, 59 patients have tested positive for the virus — an increase of three from yesterday’s numbers. Forty-four patients have tested positive for the virus at TestMV.

The hospital also reported on Monday that a patient had been hospitalized over the weekend in fair condition.

The patient was released from the hospital Tuesday in good condition, according to spokesman Marissa Lefebvre. Two Covid-19 patients have now been admitted to the hospital in October, after the Island went the entire summer without a Covid-19 hospitalization.

Including the five new patients Thursday, the Island has now eclipsed the 100 positive test mark, with a total of 103 patients having tested positive for the virus. An additional 24 patients have either tested positive for viral antibodies or been symptomatically diagnosed with the virus.

Statewide, case numbers have continued to climb, with the state Department of Public Health reporting more than 1,000 new cases for five straight days. Hospitalizations and the seven-day average positive test rate have also nearly doubled since lows in mid-September, according to the DPH.

This story has been updated to clarify that one of the original five new cases reported Thursday was tested off-Island and has not been an Island resident for several months, according to health agents. The story and headline has been edited to reflect that change.