The U.S. has been experiencing a major shortage of COVID tests since the Omicron variant struck this winter. And as Americans are forced to wait in long testing lines, or scramble for a limited number of at-home tests, health experts say that working-class people are getting hit hardest by the testing shortfall.

The U.S. has chosen a multi-pronged approach to increase testing in the country. The Biden administration is distributing 500 million rapid COVID-19 tests for free to Americans who request them, while also requiring private insurers to cover the costs of up to eight over-the-counter at-home tests a month. But a surge in Omicron-related demand and diminishing supplies of at-home tests means that it’s difficult for people to access tests in stores.

As a result, Americans are waiting in line for hours to get antigen or PCR tests from health clinics, and spending several days waiting for a result, which can render them effectively useless. And home tests, if you can find them, range in cost from $10 all the way up to $50, far above what many people can comfortably pay.

“The problem right now is: If you get sick, you don’t have a paycheck. Trying to avoid getting sick, you don’t have a test that helps you avoid getting sick,” Amitabh Chandra, professor of Public Policy at Harvard Kennedy School, tells Fortune.

It’s not just a matter of sky-high testing prices. Being able to take time off work, get to a testing site, and potentially pay for a PCR or antigen test is not feasible for many working Americans.

The disparity in testing access means minority and low-income populations will struggle with COVID a lot more, Chandra notes.

Any test result delays can also be financially disastrous for workers who test positive, and need a negative test to get back to work. People who test positive for COVID, and who are required to isolate, are not eligible to receive weekly jobless compensation, Michele Evermore, a senior policy advisor for unemployment insurance at the U.S. Department of Labor, told CNBC. And around 69.4 million U.S. workers, or around four in 10 workers, are ineligible for emergency paid sick leave benefits if they get COVID, according to an analysis from the Kaiser Family Foundation.

Increasing transmission

Working class people are often unable to work remotely.

“A lot of low wage workers don’t have the option to work from home,” says Chandra.

That means that people who are unable to spend time getting tested, or unable to afford tests, can increase the transmissibility of the virus.

“Undoubtedly, this is going to result in more transmission in communities where there is a delay in access or poor access to the testing,” Dr. Wafaa El-Sadr, Professor of Epidemiology and Medicine at Columbia University, tells Fortune.

U. S. Policies

While lines forming around testing sites seems to be a global phenomenon, different policy decisions have led to higher prices for rapid antigen testing in the U.S. compared to other countries.

A lack of upfront federal investment, higher upfront costs to buying a test which then has to be reimbursed by private insurance providers, and more stringent regulatory framework set forth by the FDA may have hindered the availability and access of rapid at home testing in the U.S.

Before Christmas, lines also formed outside European pharmacies for antigen tests, but in most countries, the tests were completely free. In Italy, Germany and France, rapid antigen tests at pop-up testing sites or pharmacies cost nothing, while at-home tests cost around five euros.

Some policy experts say that free antigen testing for all Americans would alleviate the unequal burden that low-income people face trying to find COVID tests, and help reduce transmission. It could also free up the burden currently on PCR tests, which are experiencing huge backlogs and delayed results.

“You hear people are waiting weeks to get the results of the test, which makes the test of absolutely no use at all,” says El-Sadr.