Gov. Charlie Baker said the state is working with the Army Corps of Engineers to identify sites that could be repurposed as medical facilities to treat coronavirus patients and is opening emergency child care centers for critical workers as confirmed COVID-19 cases rose by more than 100 on Saturday.

The state’s Department of Public Health announced Saturday night that a Middlesex County woman in her 50s had died from coronavirus-related illness. The woman had a pre-existing condition predisposing her to more severe disease. The state’s first death from the pandemic was announced Friday, a man in his 80s from Suffolk County. The man had been hospitalized and also had pre-existing health conditions that put him at higher risk for COVID-19.

Baker said the state and the Army Corps are looking at both public and private facilities, including college dormitories, large venues, and recently closed nursing homes, which “could possibly be either converted or modified to provide additional medical care capacity.”

“We’ve already identified a number of possible sites,” Baker said in a press conference Saturday. The conversations have also included Boston Mayor Martin Walsh, Baker said.

The governor said the Army Corps has a “cookbook of models” for how buildings can be repurposed and that some colleges have already expressed interest in working with the state.

Baker also announced that more than 300 sites will open Monday as “emergency drop-in child care services” serving first responders, medical workers and “critical service workers” such as grocery store employees.

The number of confirmed COVID-19 cases in Massachusetts climbed to 525 on Saturday, up from 413 on Friday. The Massachusetts Department of Public Health said 51 patients have been hospitalized. Out of 3,031 patients tested for the novel virus, 328 have been positive.

Middlesex County continues to have the highest number of cases, with 177. Suffolk County is the next highest with 108. Dukes and Nantucket have now reported one case.

An inmate at the Massachusetts Treatment Center in Bridgewater tested positive for the virus Friday, the Massachusetts Department of Correction said Saturday. The inmate and his roommate, who has not shown symptoms, have been quarantined from each other and the general population at the medium-security prison for sex offenders and sexually dangerous persons.

The positive COVID-19 result comes as Suffolk District Attorney Rachael Rollins and lawmakers such as U.S. Rep. Ayanna Pressley and U.S. Sen. Elizabeth Warren call to reduce prison populations to stem the spread of the virus. Advocates are similarly calling to lower the number of ICE detainees at the Bristol County House of Correction.

Tufts Medical Center had 12 employees who have tested positive for the virus as of 3:30 p.m. Saturday. All of the employees are self-quarantining at home, a hospital spokesman confirmed to the Herald. Brigham and Women’s Hospital also reported nine employees who had tested positive as of Friday night.

Baker again declined to issue a shelter-in-place order as pressure mounts from state and local officials and states such as California, New York and Illinois enact the stringent measure.

Baker said he viewed existing bans on eat-in dining and gatherings of more than 25 people as “a pretty aggressive message to the people of Massachusetts” and said, “We will continue to make adjustments based on facts as they become available.”

He said it is “perfectly appropriate” for cities and towns to take further steps. Somerville, for instance, has announced that personal services and retail establishments, including nail salons and barbershops, will temporarily close beginning Sunday.

As the virus spreads in the Bay State, testing capacity is on the rise. There were 962 tests completed Friday, up from 520 on Wednesday. Testing capacity has also grown at state and commercial labs, up to 1,144 on Friday from just under 700 on Wednesday. Drive-thru testing began Saturday at the AFC Urgent Care in Waltham, in addition to the CVS Shrewsbury pilot location announced Thursday, Baker said.

He added, “As the testing numbers go up, and as the criteria by which you can be tested expands, we certainly expect we will see an increase in the number of positive test cases as well.”

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