Most Americans have been slow to adopt telemedicine, but that situation has changed dramatically in the last few weeks. As more people have been trying to avoid emergency rooms, they are seeking urgent care over their phones or through an app on their mobile devices or computers.

Large telehealth companies, Teladoc Health and Amwell, reported unprecedented daily volume in calls and virtual visits. Amwell, headquartered in Boston, told WGBH News that their call volume has more than doubled in Massachusetts in the last week and more than 150 percent nationwide. Calls to smaller companies like Firefly Health, a Boston-based startup, have also more than doubled.

The surge in calls to direct-to-consumer companies includes patients who want to be screened for the novel coronavirus. It also includes those who are looking for help with anxiety or depression, both of which have been on the rise as people hunker down in their homes during the global pandemic. At the same time, more hospitals in Boston and around the country are providing remote care to protect medical professionals and other patients.

With consumer demand growing, Gov. Charlie Baker mandated earlier this week that all insurers cover medically necessary telemedicine visits. His administration further expanded access this week when he announced that all licensed physicians in other states may provide telemedicine services across state lines. And Medicare, which historically had many restrictions around telemedicine, announced Tuesday that all virtual care will be covered.

Brighton resident Allie Mellen made use of this trend after attending a big security conference in San Francisco in late February.

“That was right when San Francisco declared the state of emergency," Mellen said. "I came back from that trip and I started to feel a little sick. I had like a mild sore throat, a little bit of a runny nose. So immediately I just texted them on the care app."

Mellen texted her doctor at Firefly Health. Being able to get a response almost immediately, she said, comforted her.

“They told me not to worry, that it most likely wasn't corona,” Mellen said. “I wasn't super worried about it being coronavirus because I didn't have a fever, but I just wanted to keep them updated.”

Mellen found herself contacting her doctor through the app once again after receiving some bad news.

“On Tuesday, March 10, I found out that two people at the conference who were really close to our booth got very sick and they had coronavirus," she said. "One was in a coma.”

Her physician, Nisha Basu, contacted the Massachusetts Department of Public Health to discuss Mellen’s case. Given the shortage of testing kits, Mellen didn’t meet the criteria to be tested at the time. She’s now fully recovered from whatever she had. But Basu says the nature of Mellen’s virtual visits reflect an overall surge in calls and virtual visits.

“I think that has coincided with the both the changes of patients who have concerns about their own health, about how to keep themselves safe and also how to access care should they become sick during a time where it's not advisable to go to an ambulatory care setting's waiting room,” Basu said.

Still, there are limitations to telehealth. Patients can’t get x-rays, for example, and it’s not a good approach for treating acute illnesses. Some specialties are better suited for virtual care, but for anyone who doesn't have a computer or smartphone, video visits are not an option.

Yet, Michael Barnett, assistant professor of health policy management at the Harvard T.H. Chan School of Public Health, said this health crisis could be the sea change that pushes telehealth into the mainstream.

“Up until this point in the U.S., we've really not done a very good job of using that whole spectrum to its full potential,” he said.

Barnett, who is also a physician with Brigham and Women’s Hospital, said the current crisis is forcing healthcare providers to rethink all levels of in-person interaction.

“Now everybody is going to be considering what is the most appropriate level of interaction to give this patient, what they need, given the risks and benefits," he said. "And I think the way that we just view health care delivery in general is going to change because people will get used to a different way of thinking about does this patient need to actually be seen in person?”

Barnett has already shifted towards meeting with his patients virtually or over the phone. Boston-area hospitals such as Beth Israel Deaconess Center and Tufts Medical Center have also told WGBH News that they are rapidly shifting their outpatient care to telehealth platforms in order to adhere to social distancing recommendations. In the last week, Tufts enrolled all of its healthcare providers to the telehealth platform Amwell and is training everyone on how to use it. They will soon notify patients and offer to reschedule in-person appointments as telemedicine visits.

"Telehealth is central to our social distancing program," said Dr. William Harvey, chief medical information officer for Tufts Medical Center. "We did not really have a robust telehealth solution at the time this crisis started, so we worked rapidly to put in place a solution."

Peter Antall, chief medical officer of Amwell, said the company is receiving a groundswell of requests from hospitals scrambling to provide outpatient care in this new age of social distancing.

“In Massachusetts and throughout America, hospitals are adopting rapidly. We're getting requests that are shocking to us,” Antall said.

Amwell runs its own direct-to-consumer telehealth app but also provides platforms for hospital systems nationwide.

“We had one very, very large multi-state hospital system that wants to get 1,000 doctors enrolled in the next week," he said. "So it really is a revolution.”