Since the 1960s, telehealth cheerleaders have been predicting that video visits with doctors would soon become common for many U.S. patients. That became true only weeks ago, six decades later, when the coronavirus pandemic essentially shut down the world.

“Since about mid-March, it’s become a reality and even a likelihood for millions of patients,” said Lori Uscher-Pines, a senior policy researcher at the Rand Corp., whose research includes innovations in telehealth. “Before then, less than 10 percent of U.S. adults had ever had a telemedicine visit. But covid-19 [is changing] all that, likely permanently.”

The terms telehealth, telemedicine and e-health have nuances when used legally, but for consumers, they are usually used interchangeably and refer to health care provided by a professional in a non-face-to-face manner, says Mei Wa Kwang, executive director of the Public Health Institute’s Center for Connected Health Policy in Sacramento. Options can include a phone call, email, text, video visit or even a video email.

Before mid-March, Jay Mazel, a cardiac electrophysiologist at MedStar Washington Hospital Center in Northwest Washington, never gave much thought to telemedicine. His specialty involves the treatment of heart rhythm problems. While he’s still doing emergency procedures, with enhanced safety protocols, two days a week, maintenance visits are largely by video.

“Even though it’s brand new for my patients — who tend to be older — and their doctor, they love it and so do I,” says Mazel, who does a lot of the televisits from home.

Mazel says he does think the first visit with a new patient should be in person if possible, “to help us establish rapport.” But for now, both he and his patients are happy with the information they are able to exchange during virtual appointments for uncomplicated routine follow-ups.

Nationally, telehealth visits, including for symptoms of covid-19, the disease caused by the coronavirus, are projected to climb to 1 billion by the end of 2020, according to Forrester Research. The uptick started in mid-March when state stay-at-home orders began. Partners Healthcare, for example, a Massachusetts-based health-care system that includes Massachusetts General and Brigham and Women’s hospitals, had 1,600 televisits for outpatient care in February, 89,000 in March and 242,000 in April. Jefferson Health, a health-care system in Pennsylvania and New Jersey, saw a 11-fold jump from February to end April.

Telemedicine was largely ready for the influx.

The past decade or so has been full of telehealth demonstration projects, including video visits with specialists, for people living far from academic medical centers. Several dedicated telehealth companies have sprung up, often catering to people with no insurance or high deductibles. Each telehealth company has different offerings — but a common visit such as checking symptoms for flu, generally costs under $100 per visit. The limiting factor, Kwang says, had been that most people have little or no health insurance coverage for video visits and doctors often have not been able to be reimbursed for telehealth services.

Amid the covid-19 outbreak, that has changed.

The increase in telehealth visits has been bolstered by decisions to cover them by Medicare, Medicaid and many private insurers, some of whom have even waived co-pays and deductibles for some visits, especially for ones related to covid-19 symptoms, according to information from the industry’s association, America’s Health Insurance Plans. Aetna, for example, is “offering zero co-pay telemedicine visits for any reason,” and Humana is “waiving member cost share for all telehealth services delivered by participating/in-network providers.”

Emily Shevitz, 30, of Kendall, Fla., was grateful for her first televisit in mid-March when she couldn’t get a headache under control, a chronic condition since a near-fatal car accident in 2012.

“Because of a weak immune system, I didn’t want to go to urgent care or my primary-care clinic, out of concern I could contract the virus,” she said. Shevitz accessed a telehealth visit through Baptist Hospital in Miami. “I was able to talk to an ER doctor who asked me about my medical history and prescribed . . . medication until I could see my neurologist. It was reassuring that I was able to be seen from the comfort of my own house.”

Joe Kvedar, vice president of Connected Health at Partners HealthCare and president-elect of the American Telemedicine Association, which represents the industry, recommends calling insurers to determine telehealth coverage and options. If a doctor does not offer televisits, the insurer may be able to connect the patient to a firm that does, often at no charge or a small co-pay.

Other tips include checking whether any information or forms must be signed, having an ID number or password ready if a practice requires them to connect to the visit, finding a quiet and private place for the visit, and charging the device the patient is using.

In March, the Department of Health and Human Services issued a notice that because of the covid-19 emergency, Medicare would pay doctors and hospitals for a broad range of telehealth services, including those delivered by nurse practitioners, clinical psychologists and social workers at the same rate as in-person visits.

The guidance also allows doctors to use any technology they choose to deliver care and treat patients via telehealth even if it’s not related to the virus outbreak.

For Medicaid, run by each state individually, waivers can be submitted to change to telehealth delivery. In Colorado, the state has added telephone and live chat visits to video visits that were already allowed.

“If Medicaid continues to allow these visits, as we hope, after the emergency is over, many of my patients can access care without the need to travel or take time from work,” said Kyle Knierim, a family physician in Colorado and associate director of Practice Transformation in the Department of Family Medicine at the University of Colorado School of Medicine.

Telehealth, however, hasn’t been, and can’t be, a replacement for every health visit.

An April 23 study, published by the Commonwealth Fund, analyzed data on changes in visit volume for more than 50,000 health-care providers and found that the number of visits to physician offices declined nearly 60 percent in mid-March from Feb. 1 and has remained low through mid-April. Telehealth accounted for only 30 percent of visits that were still happening, but it did not make up for the much larger decline in visits.

For the week of April 5, for example, ophthalmology saw the biggest drop in in-person visits, a loss of 79 percent. Behavioral health was least affected, but still saw a drop of 30 percent. Alarmingly, pediatric in-person visits saw a drop of more than 60 percent.

“Telemedicine volume has grown too modestly to make up for lost in-person visits,” said Eric Schneider, senior vice president for policy and research at the Commonwealth Fund. He says that in-person visits will still be needed for diagnosis and testing of some complex conditions.

“It really is important to be very aware of the limitations,” says Anthony E. Magit, a pediatric otolaryngologist and chief of physician integration at Rady Children’s Hospital in San Diego, where telehealth visits have jumped from just a few before the pandemic to as many as 800 per day recently.

Those limitations include brief visits that focus on a single issue and may not include questions that lead to other health concerns as often happens during in-person visits, lack of privacy for some patients and lack of certain tools sometimes used in visits, such as smartphone cameras that allow doctors to see throats and ears, and pulse oximeters or blood pressure monitors that give doctors critical patient data.

“We don’t want to create a solution that makes the situation for underserved individuals worse,” Magit said. “It’s our responsibility to advocate through legislators and payers to make sure that the divide doesn’t get wider because of telemedicine.”

In a report published May 11, researchers at the Kaiser Family Foundation said that “service parity and payment parity for telehealth across all insurers would help increase access for patients.”

Once the Centers for Medicare and Medicaid Services released the new rules on telemedicine visits in March, the American Medical Association and other medical societies such as the American Academy of Pediatrics and the American College of Obstetrics and Gynecologists kicked into high gear to advise their members on the rules and telehealth best practices. Wide use of telemedicine is so new that the AMA released a primer in March.

The AAP, for example, has posted clinical suggestions on its website including “consider[ing] . . . adjustments to . . . clinical operations [such as] only conduct[ing] well [in person] visits for newborns, and for infants and younger children who require immunizations and to reschedule well visits for those in middle childhood and adolescence to a later date.”

The same is true for patients who need urgent follow-up testing. But if recent screening exams, such as a mammogram, were normal, physicians are likely to wait for the outbreak to abate in their communities before recommending additional testing, said Mark B. Woodland, OB/GYN chair at Reading Hospital/Tower Health and Drexel University College of Medicine and the chair of the Council on Resident Education for the American College of Obstetrics and Gynecologists.

Analysts and doctors do not expect the “genie of telemedicine to be put back into the bottle” once the crisis ends, Woodland said.

“The silver lining is that we will learn how to do it well, and our patients will help us learn how to do it even better.”

Schneider said he expects that even once the pandemic ends, physicians will probably create “hybrid practices” that mix telemedicine and office visits.

Therapydia DC, a physical therapy practice in Northwest Washington, had offered only telehealth visits since mid-March but expects to offer both televisits and office visits — once the city begins to allow offices to reopen.