A more virulent strain of the Covid-19 virus has been identified on Martha’s Vineyard, hospital officials confirmed Friday, after positive test samples were sent to a state lab for variant testing due to a recent case surge on the Island.

At an impromptu press briefing Friday afternoon, hospital head of operations and chief nurse Claire Seguin said that three of the six samples sent to the state epidemiology lab came back positive for the B.1.1.7 virus variant that originated in the United Kingdom. One of the six samples came back negative for all variant strains, and two are still pending, Ms. Seguin said.

The returned samples did not come back positive for any other virus variants, officials said.

The B.1.1.7 variant, which officials said is more contagious than the original virus strain, has previously been identified in Cape Cod and Nantucket. There have officially been more than 1,000 cases of the variant identified in the commonwealth, according to the Center for Disease Control.

At the briefing Friday afternoon, Ms. Seguin said that she had proactively requested the state to conduct the testing after case numbers shot up last weekend. The hospital, boards of health and state DPH then worked together to choose cases that were determined to be high risk, Ms. Seguin said, settling on six to send to the state lab.

Ms. Seguin said those chosen samples were generally associated with a large number of other cases, or involved cases in which patients had traveled. Ms. Seguin said she was not surprised by the results.

“I was not surprised, because our case counts were going up. I was actually suspicious of it,” Ms. Seguin said. "But still, disheartened, and makes me [want to] double down on our protocols.”

Known to be more virulent, the B.1.1.7 variant spreads faster and, in some studies, has been associated with sicker patients. The state is expected to return results from the other two positive test samples next week.

Ms. Seguin said that one patient is currently hospitalized with the virus, in fair condition. Hospital officials cannot disclose whether the patient is infected with a virus variant, Ms. Seguin said. The hospitalization marks the first hospitalized patient since February, when cases began to dramatically decline on the Island after a post-New Year spike.

In a Friday case update, Tisbury health agent Maura Valley said that 25 patients had tested positive for the virus since Wednesday, including 20 new positive tests on Friday alone. Seventeen were tested at the hospital, and eight came from TestMV.

The recent case numbers continue an alarming recent spike on the Island, in which more than 150 patients have tested positive for the virus in the past two weeks — the largest number since the pandemic began.

“This is such an important reminder of the need for us to remain vigilant, and work together as a village,” Ms. Seguin said. “Even after you’ve been vaccinated, you must wear a mask, sanitize your hands, and social distance. It’s not the time for gatherings.”

The Island has now recorded 1,154 positive PCR tests since the pandemic began. No Island patients have died from the virus.