Andrew Parys, 36, said he didn't pay off his prosthetic leg at the end of March as planned because he didn't know whether he'd be able to afford groceries. He worked as a bartender in Hershey, Pennsylvania, until the coronavirus pandemic shuttered the business last month, leading him to be one of the millions of Americans who signed up for unemployment over the past two weeks.

While Parys' employer maintains his health insurance for now, he expects to lose it soon. His fiancée, Tara Delutis, 31, meanwhile, was furloughed from her job managing a spa and lost her coverage. That leaves her with few options to treat her fibromyalgia and endometriosis. Now both are worried they won't be able to pay their medical bills without health care coverage.

"I can't believe it's 2020, we live in the richest country in the world and we have to be under so much stress about health care," Parys said.

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More than 156 million Americans depended on their employers for health insurance before the pandemic. But now, with almost 10 million people filing new unemployment claims over the past two weeks, an estimated 3.5 million workers likely lost their employer-provided health insurance, according to a study from the Economic Policy Institute.

In response, an overwhelming number of people are expected to sign up for Medicaid, the state and federal program that provides more than 70 million low-income people with health care coverage — pushing it to the breaking point.

Washington state has gotten a significant increase of about 35,000 new applications over the past 10 days, the Washington State Health Care Authority told NBC News. The Michigan Department of Health and Human Services said 12,000 more applications have been submitted over the past week than a month ago.

If unemployment continues to grow, an additional 10 million to 20 million Americans could enroll in Medicaid and millions could live without coverage altogether, a study published on Friday found. Insurance provided by employers could drop by 11 million to 23 million.

"You definitely see in the data that as unemployment goes up, the Medicaid rolls go up," said Josh Bivens, the Economic Policy Institute's director of research. "That's good, and it's supposed to happen: It's a safety net. But this is a quick enough shock that it could be a huge financial burden on Medicaid systems across the states."

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When unemployment rose by 1 percent during the recession, health care professionals assumed that meant 1 million more people applying for Medicaid, experts said. Because the passage of the Affordable Care Act in 2010 allowed states to expand Medicaid and cover more people, the number is expected to be much higher this time.

The 14 states that didn't expand Medicaid, however, will likely have a more difficult time paying for care because they don't have access to the same amount of federal money as those that did.

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Coronavirus legislation that has passed so far has provided states with billions of additional dollars to support their Medicaid programs, as well as a 6.2 percent increase in its federal matching rate. However, experts warn that that won't be nearly enough as demand continues to increase, the cost of caring for a sick public grows and states' tax revenue plummets because of closed businesses.

"More money is going to have to flow," said Andy Slavitt, who was head of the Centers for Medicare and Medicaid Services during the administration of former President Barack Obama. "There was something that almost got into the third bill that would have created a recessionary bump in Medicaid when unemployment jumped. Republicans didn't want it, but it's a good addition."

Experts warn that something will have to be done or it could lead to shrinking coverage. States with tight budgets may begin to make difficult decisions about the amount of care they provide to people, especially if they run low on ventilators and intensive care beds.

That is a particular point of worry for Eliot Fishman, a senior health policy director at the consumer group Families USA who was a top Medicaid official in the Obama administration.

"If states are in a position where they don't have enough federal funds and they don't have enough state funds and state revenues are crashing, also, I'm concerned that bad decisions around rationing care might happen, especially if this all becomes very expensive," he said.

Loss of access to health insurance will put millions in vulnerable positions, especially after the Trump administration decided it wouldn't allow a special enrollment period for people to sign up for coverage through the Affordable Care Act.

While 11 of 12 states that run their own health care exchanges have decided to create a special period for sign-ups, the remaining 38 states depend on the federal government to operate their programs and won't be able to afford the same opportunity to their residents.

"It is the easiest low-hanging fruit that will provide some relief," Bivens said. "If you lose your job, you are allowed to go to the ACA exchanges, but it requires some documentation of job loss and loss of previous coverage. Whereas if, instead, they did a special enrollment period, you wouldn't have to go through those bureaucratic hoops."

Another concern is whether states have the institutional framework to address the surge in demand. Multiple states have reported their unemployment websites crashing, and many have complained that they are unable to reach their state offices on the phone — some are even unable to pay out all the unemployment claims they have received.

"A sleeper issue for this is the ability for states to process this surge in enrollment," said Joan Alker, executive director of the Center for Children and Families at Georgetown University's McCourt School of Public Policy.

"States have had to move to telework, many are understaffed to begin with and some of their workforce may get sick," Alker said. "I very much doubt most states can move to telework as easily as, let's say, Google."

The dialogue around the topic has some health care advocates particularly upset.

Wendell Potter, a former health care executive turned "Medicare for All" advocate, warned that sudden layoffs would show how imperiled the American health care system is.

"With the loss of jobs for most of those people is the loss of health insurance," he said, "so it's inescapable to see how unreliable this is and how absurd it is for their access to health care be tied to where they work."