For Many Pandemic Victims, Lingering Effects Stress Insurance Coverage

“I have been too ill to deal with the bills and have been focused on mainly trying to feel better,” said Ms. Sales, 41 years old, who had qualified for a Medicaid program for people with high medical expenses that reduce their income. Some of her medical bills are being sent to collection agencies.

Ms. Sales is among a group of patients, the exact size of which is unknown, developing long-term medical problems from Covid-19 that require extended—and often expensive—medical care, stressing families’ financial security and taxing an already strained health system.

A number of doctors and researchers are warning the fallout from people who develop long-term health effects from coronavirus could ripple through the U.S. economy, burdening public safety-net programs such as Medicaid while leaving many patients with significant medical debt.

“We need to mobilize the medical community as a whole, and that’s going to cost money,” said Zijian Chen, director of Mount Sinai Health System’s Center for Post-Covid Care. “It affects patients’ ability to work, and that has major implications as well for the economy.”

Covid-19, in some cases, can be lethal, killing more than 170,000 people in the U.S. so far. Other victims of the virus see no symptoms after a recovery that can take as little as a week or two. But a third category reports symptoms that linger for weeks, sometimes months, including extreme fatigue, shortness of breath, neurological issues and irregular heart rhythm.

There is little comprehensive data, as of yet, on how many people have long-term health symptoms, known as long-Covid patients or long-haulers. “Longer-term complications don’t fit into a box,” said Ben Linas, an epidemiologist at Boston University School of Medicine.

And yet, doctors caring for these patients say the number is substantial. About one-third of 270 nonhospitalized adults who tested positive for coronavirus said they hadn’t returned to normal health two to three weeks later, according to a survey published recently by the U.S. Centers for Disease Control and Prevention.

Eighty-seven percent of patients who had recovered from Covid-19 reported persistence of at least one symptom 60 days later, particularly fatigue and shortness of breath, according to a July 9 study by Gemelli University Hospital in Rome.

A picture is emerging of prolonged insurance coverage needs as a sharp economic downturn between February and May has left 5.4 million workers newly unemployed and uninsured, according to Families USA, a consumer health advocacy organization. Minorities make up a disproportionately large number of the newly unemployed, and thus uninsured.

Congress, the Trump administration and insurers took steps early in the pandemic, before evidence of Covid-19’s aftereffects was clear, to soften the financial blow. Those measures included government reimbursement at Medicare rates for hospitals treating uninsured Covid-19 patients and ensuring that testing would be free. Most large insurers waived out-of-pocket costs for Covid-19 treatment.

Hospital leaders now worry federal reimbursements will run out. “There is more that needs to be done,” said Tom Nickels, at the American Hospital Association. “The answer is that people need to have coverage.”

As of July 30, the Department of Health and Human Services had reimbursed more than $347 million in treatment claims. But the funding is also being used to provide grants to a host of providers, from nursing homes to dentists, and the total cost to the U.S. health system just from inpatient hospitalizations due to Covid-19 is projected to reach up to $17 billion in 2020, according to a June report from Avalare Health, a Washington-based health-care consulting firm.

Some patients are raising alarm about the medical costs in Facebook support groups such as Covid-19 Long-Haulers Discussion Group, which has nearly 5,000 members, and Long Covid Support Group, which has 18,000 members.

“My medical bills are astronomical, and all new medications run close to $500 a month now,” according to one post in the Long Haulers group. “My husband lost his longtime job because of the amount of time he had to take off because of this. We are drowning in expenses.”

Treatment for post-Covid 19 symptoms can include repeat computerized and magnetic resonance scans, home health care, treatment for strokes and blood clots, rehabilitation and dialysis. It could be years before final costs are known.

Premiums are rising at 5%, far higher than wages and more than double inflation, according to a September 2019 Kaiser Family Foundation survey. Workers last year contributed $6,015 toward the cost of family coverage on average, with employers paying the rest.

A single computer-imaging scan can run up to $5,000. A complex echocardiogram can cost as much as $2,000.

“I have been on the verge of calling 911 many times over the last few months, but cannot afford the hospital bill,” said Joy Nelson, 63, an artist and web developer in Tamarac, Fla., who was infected in March and still has symptoms. She has a $6,800 annual deductible.

Long-term Covid patients are filing for disability or applying for Medicaid, some health advocates say, but 12 states haven’t expanded the program and many of those states have high case counts. Florida and Texas together have more than one million cases and didn’t expand the federal-state program for low-income and disabled people.

States that did expand Medicaid also are bracing for costly treatments that may be needed. Federal and state Medicaid costs just for Covid-19 hospital expenses are projected to reach as much as $780 million in 2020, according to Avalere, just as states are seeing the recession drain their tax revenues.

Not all patients diagnosed by doctors with long-term symptoms have tested positive for coronavirus because tests were in short supply in March and in most cases reserved for high-risk people. Even now, people in some parts of the country face long waits for tests.

That complicates insurance coverage. Hospitals and other providers aren’t eligible for the federal stimulus fund that reimburses them for treating uninsured Covid-19 patients if it wasn’t their primary diagnosis.

Jenifer Johnston, 40, of Vancouver, Wash., provided distribution services for a soft-drink company when she became ill in March. She had been sick for eight weeks before a doctor told her it was post-Covid-19 related. Ms. Johnston said she had been told there weren’t enough tests available to test her for coronavirus when she fell sick.

She has a $2,000 deductible she must pay and doesn’t know yet how much her medical bills will be because some of the treatment she has received wound up being out-of-network. Congress has so far not passed legislation to protect patients from surprise out-of-network hospital bills.

Ms. Johnston had a fever for three months and pneumonia in her left lung. She said the left side of her body goes numb and her heart races as fast as 180 beats a minute when she stands up.

“I can still barely walk,” she said. She has used up her employer’s Family and Medical Leave, she said, and is living off her savings. “They referred me to a specialist out of network, but I can’t afford to see them.”

—Paul Overberg contributed to this article.

Write to Stephanie Armour at stephanie.armour@wsj.com