Three Boston hospitals reported Wednesday that a combined 100 of their employees have tested positive for the new coronavirus.

The deadly virus, which has already prompted the area's medical centers to hunker down in anticipation of a massive surge of cases -- Massachusetts has reported more than 1,800 cases and the coronavirus can take days to present in infected people or worsen enough to send them to the hospital.

Brigham and Women's Hospital said it has 45 employees who have tested positive for COVID-19, the disease caused by the new coronavirus, as of Wednesday afternoon.

At Massachusetts General Hospital, 41 hospital employees have contracted the coronavirus, though the institution noted in a statement that "it is believed that the vast majority of these individuals did not contract the virus at work."

At Boston Medical Center, 15 employees have tested positive, the hospital said.

Researchers are optimistic that an antiviral drug will shorten recovery time and reduce the side effects of the virus.

The major interventions in public life ordered recently in Massachusetts and around the country -- school closures, bans on most gatherings and more -- are aimed at slowing the spread of the coronavirus so the number of patients doesn't overwhelm hospitals. In Italy and other hard-hit countries, doctors have been working around the clock to deal with the onslaught.

Doctors at Massachusetts General have already found themselves in a marathon, one said earlier Wednesday, with no end in sight.

"Even our amazing team is getting worn down," said Ali Raja, who runs the hospital's emergency department. "They aren't used to having this kind of stuff affect their daily lives at home. that's what's so different about this."

The virus is highly contagious and has already deeply strained hospitals' reserves of personal protective equipment, including at Massachusetts General, whose president last week asked people with 3D printers to help make masks in an effort to keep his staff protected.

There is a need for supplies at Massachusetts General Hospital where N-95 masks and face shields are running low amid the coronavirus pandemic.

Without adequate masks, gloves, gowns and more, doctors and nurses are more likely to contract the virus themselves. Many local emergency room physicians have been forced to use the supplies sparingly.

“Practicing medicine in this country, you don't think of needing to ration supplies,” said Dr. Joshua Lerner, with Wachusett Emergency Physicians at Leominster Hospital.

He said the staff there has begun using the same mask for half their shift – about four hours at a time – in an effort to conserve their current supply.

“We can remove the mask without touching the front of it. We put it in a paper bag with our name on it," Lerner said, noting that it's clearly not a perfect solution and echoing others' calls for companies to step up and help out however they can.

State lawmakers are asking businesses or anyone with access to masks to donate them as supplies run low.