When the pandemic hit, the little health center on Vinalhaven, an island 15 miles off the coast of Maine, was prepared in ways many larger facilities were not. The Islands Community Medical Services had long been using telehealth to provide primary and behavioral care to its 1,500-strong year-round community, relying on grants to cover costs. As the public health emergency lifted many restrictions on virtual care, the clinic ramped up its offerings.

"We were able to pivot pretty quickly," said former operations director Christina R. Quinlan, describing a scramble to add specialized medical and social care.

Across the country, in urban and suburban settings, the same pattern played out as federal and state regulators issued scores of waivers to telehealth access and coverage rules, making it easier for hospitals, health centers, and clinics to offer a wider range of remote services and be reimbursed for delivering them.

A question that remains to be answered, experts say, is how many rules will tighten once the public health emergency is over. This summer, more than 430 health-related organizations, including hospitals, professional bodies and patient-advocacy groups, urged congressional leaders to keep the gateways to telehealth open, arguing that much of health-care delivery has moved online “not only to meet COVID-driven patient demand, but to prepare for America’s future health care needs.”

Lawmakers on both sides of the aisle have shown support for making the shift to telehealth permanent through mechanisms such as the Connect for Health Act. But many states have already rescinded the licensing waivers that allowed clinicians and some other providers to practice across state lines, or are preparing to do so. Other decisions at the state, federal and individual health-care system levels remain uncertain.

“It’s frustrating,” said Steven A. Epstein, chair of psychiatry at Georgetown University School of Medicine, who said the pandemic not only fixed logistical challenges for physicians treating patients in adjoining states but offered many clients welcome convenience when they were able to connect with therapists without having to show up at a clinic.

"The no-show rates dropped off significantly," said Epstein, who has heard of patients who now drive across state lines to talk to therapists from their cars.

Over the last 18 months, providers have revamped their practices, taking advantage of the pandemic-fueled flexibility that allows consultations in people’s homes rather than in approved clinical settings and via phone instead of only on video. Some have been using platforms that did not meet pre-pandemic standards for privacy and security. Many have invested in new computer systems and signed up for training in a new skill for the modern tech-savvy physician — a good “webside” manner. (Rx for doctors: Look into the laptop camera, not at the screen.)

“The floodgates opened during COVID,” said Danielle Louder, program director for the Northeast Telehealth Resource Center, which supports the growth of telehealth in New England and New York.

Kimberly Brandt, a partner at the consulting firm Tarplin, Downs & Young and former principal deputy administrator for operations and policy at the Centers for Medicare and Medicaid Services, known as CMS, said that in areas such as behavioral health, the uptick has been too big to reverse. But she wondered whether the range of covered services, which expanded to include physical and speech therapy, would continue.

"In general, I do not see us going back," Brandt said.

Among many telehealth-related changes CMS is proposing in its 2022 Medicare Physician Fee Schedule, it would allow certain pandemic-era services to continue through 2023 to evaluate whether they should be made permanent.

Some of the proposals could be accomplished through regulatory changes; others would require acts of Congress.

In a Washington Post Live interview, Xavier Becerra, secretary of the Department of Health and Human Services, said: "We are absolutely supportive of efforts to give us the authority to be able to utilize telehealth in greater ways. We want to make sure that we don't leave anyone behind."

Telehealth’s pandemic-driven rise in popularity reflects patients’ widespread appreciation of flexibility in how and where they seek care. In March and April of 2020, the Mid-Atlantic Telehealth Resource Center, one of 14 Health Resources and Services Administration-funded regional centers, received more than 400 inquiries from providers — an 800% jump over the same two months in 2019.

Questions frequently came from clinicians whose patients are covered by Medicare and Medicaid, as CMS issued dozens of waivers of its pre-pandemic regulations, including opening the door to reimbursement for telehealth visits delivered in a patient's home.

The pandemic also prompted interest from private practitioners, including primary care doctors, who recognize that, going ahead, the ability to provide online visits will be necessary to retain patients and attract new ones, according to Kathy Hsu Wibberly, the Mid-Atlantic center's director.

"What we are seeing now is private practices missing out on the ability to access patients if they don't at least have hybrid access of care," Wibberly said.

What's holding up progress to even greater use of telehealth is uncertainty about the future web of state and federal regulations over public and private systems.

"That's the barrier much more than any one thing," Wibberly said. "Everything is so complex."

There are signs of support for telehealth. Congress is considering legislation that would make some changes permanent. The $550 billion infrastructure bill that the U.S. Senate passed this month included $65 billion for broadband, which should give patients in rural areas access to internet connections fast enough for video visits as well as uploading data from wearable medical devices.

And last month, the Biden administration announced a $19 million investment in telehealth in the form of awards aimed at stimulating innovation and expanding access to services in underserved areas.