Tisbury has been designated a high-risk community by the state Department of Public Health after reporting 30 positive coronavirus cases in the past two weeks — the first time a Vineyard town has received the high risk label.

In a weekly community-by-community report released by the DEP Thursday evening, Tisbury was determined to have an average daily incidence rate per 100,000 people of 51.3 cases during the period between Oct. 25 and Nov. 7. The town’s positive test rate was 4.04 per cent, nearly 50 per cent higher than the state average.

The Island’s main port town joins 30 other communities throughout the Commonwealth that were put in the red zone by the state on Thursday, including Brockton, Fall River and New Bedford.

Edgartown was determined to be a moderate risk community by the state, reporting 16 new cases in the past two weeks for an average daily incidence rate per 100,000 residents of 28. The town’s positivity rate is currently 3.15 per cent, and the town has reported 37 total cases since the pandemic began. Moderate risk communities are labeled “yellow” by the state.

The threshold for high and moderate risk communities was significantly heightened late last week, when Gov. Charlie Baker’s administration rewrote public health metrics that were generally stricter than other states in the Northeast just as case counts begin to spike throughout the commonwealth. Communities under 10,000 inhabitants are now considered high risk if they have more than 25 cases in a given two week period. Risk calculations get more complicated for communities larger than 10,000 residents, factoring in average daily case numbers and positive test rate. 

In an email Friday morning, Tisbury health agent Maura Valley confirmed that Tisbury was considered to be under 10,000 residents. 

Oak Bluffs has reported six cases in the past 14 days, while other towns have reported fewer than five.

The state uses 2019 population estimates derived from a method developed by the University of Massachusetts Donahue Institute for its metrics per 100,000 people. It is not immediately clear whether Tisbury falls in the 10,000 or 50,000 population range.

Communities that are labeled “high risk” for three weeks in a row are required by state law to revert back to an earlier step of the state’s reopening plan.

The earlier stage of the reopening plan requires all indoor performance venues to close, limits outdoor gatherings at public event venues and settings to 50 people and requires outdoor theaters and performance venues to operate at 25 per cent capacity with no more than 50 people. Museums, gyms, libraries and recreation businesses have to reduce capacity to 40 per cent (capacity is currently at 50 per cent).

State guidance also requests communities designated high risk to continue in-person education, contingent on case spread not occurring in school buildings.

State metrics regarding specific communities are released weekly on Thursday evening. Metrics were released late last week after the state heightened thresholds for community risk.

The designation for Tisbury comes as the Island has reported more than 80 total cases over the past two weeks — by far the most since the pandemic began. The state, on Thursday, also recorded more than 2,000 cases for the third straight day, and reported its 10,000th death.

Updated to include confirmation of Tisbury's population bracket.