The Martha’s Vineyard boards of health reported one new coronavirus case in their daily demographic update Thursday, bringing the Islandwide total to 24 positive cases since the outbreak began.

The new case is a female in her fifties, according to the board of health update, which went out around 4 p.m. Thursday.

The test for the new case was conducted off-Island, Tisbury board of health official Maura Valley wrote in an email to the Gazette, explaining why the case was not included in the Martha’s Vineyard Hospital daily testing update.

Because of comprehensive contact tracing protocols and the state’s online epidemiological database, MAVEN, the boards of health on Island are informed of any person residing on the Vineyard who has tested positive for the virus off-Island. The new case on Thursday appears to be the Vineyard’s first positive case tested off-Island.

The Martha’s Vineyard Hospital has reported 23 positive tests for the virus — meaning that every other positive case known to the boards of health on the Island was tested at the hospital.

For the second day in a row Thursday, the Martha’s Vineyard Hospital reported no new cases of Covid-19.

Statewide figures from the Massachusetts Department of Public Health Thursday showed a decline in confirmed cases after a one-day increase. There were 1,696 new cases out of nearly 12,000 tests performed. Another 132 people died.

In their daily testing update, the hospital reported that as of 11 a.m. on Thursday they had conducted 537 tests for the virus, with 23 positives, 513 negatives and one test still pending.

The hospital said no one was currently hospitalized with the virus. A patient hospitalized with the virus on Tuesday was discharged in stable condition on Wednesday, according to spokesman Katrina Delgadillo. Four patients have been hospitalized since the outbreak began, three of whom have been transported to Boston for care. One patient died from causes not proven to be related to Covid-19.

According to Cynthia Mitchell, executive director of Island Health Care — a community health center on the Island that has contracted with the boards of health to conduct contact tracing and case monitoring — 12 of the 24 positive cases on the Island have been completed, meaning that those patients were no longer being monitored by nurses or health agents.

“We are monitoring the positive cases until essentially they are deemed to have recovered,” Ms. Mitchell said. “So after that point we stop monitoring.”

Eleven cases are still in progress, Ms. Mitchell said, meaning that the individuals were still in quarantine and being monitored by health agents or nurses with IHC.

When a resident tests positive for the virus, they are told to go into confinement in their home and are monitored by their town health agent, unless their condition becomes more serious. After a patient in confinement has gone at least seven days since they started being symptomatic — and gone 72 hours without any symptoms — health agents can assess their condition and release them from confinement, according to a previous interview with Tisbury health agent Maura Valley.

The outbreak on the Island began with the first case in mid-March. Covid-19 case numbers then steadily grew through the beginning of April, culminating with 12 positive cases by April 2. There was a nine-day lull in which the hospital reported no new cases. Since then, there have been 11 additional positives reported, including three this past weekend.

Speaking on Tuesday about the recent spurt of cases, hospital CEO Denise Schepici said there was no clear explanation.

“More people, more prevalence,” Ms. Schepici said. “I can’t really correlate it with anything else.”

According to the most recent demographic update from the board of health, the Island has 11 male and 13 female cases. The age breakdown of cases is as follows: one individual under the age of 20, five in their twenties, two in their thirties, one in their forties, eight in their fifties and seven in their sixties.

The boards of health and hospital do not provide information on the location of the positive cases, their place of residency or on the circumstances of how the virus was contracted.

Every Wednesday, the state Department of Public Health provides information on the number of cases in particular towns, but only provides exact numbers if the specific towns have more than five positive cases. According to the most recent update, Aquinnah has zero cases and Chilmark, Tisbury and Oak Bluffs all have less than five. Edgartown has six, and West Tisbury has the most on the Island, with seven.

A spike in cases statewide on Wednesday prompted Gov. Charlie Baker to say during his daily press briefing Thursday that the state still had “a lot of work to do” to suppress the virus. The state reported 1,754 new cases and 208 new deaths, significantly higher numbers than on Monday or Tuesday. The state now has over 72,000 cases and 4,420 deaths.

Wednesday marked the first day that masks were required in public areas where people could not socially-distance, including the Steamship Authority. A state stay-at-home order is in effect until May 18.