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Cheap, rapid at-home testing for Covid-19 could take weeks or months

A health worker processes a Covid-19 antibody test for a patient at the Diagnostic and Wellness Center in Torrance, California, on May 5, 2020.

Valerie Macon | AFP | Getty Images

Medical experts say that consumers will need to test themselves in huge numbers for Covid-19 at home in order for the economy to safely reopen. But such tests that deliver a rapid result to consumers at home could take weeks, if not months, to hit the market.

The U.S. plans to make millions of accurate and easy-to-use cornavirus tests by the end of the summer and before flu season, the head of the National Institutes of Health said on Thursday during a hearing with the Senate Committee on Health, Education, Labor and Pensions.

Many companies and academic labs are working on at-home diagnostic tests. But none of these have been approved by federal regulators as yet, and it will take time before they’re readily available to consumers. What has been given a green light is an at-home collection kit from LabCorp, which still involves the patient sending a biological sample to a lab for analysis. It typically takes several days to get a result, and these tests are primarily available to health workers and first responders — at least for now. 

What could be coming soon is a different technology altogether: a so-called antigen test that can quickly detect active infections by looking for viral surface proteins. These could theoretically augment the standard PCR tests — polymerase chain reaction tests — which are the gold standard for Covid-19. These diagnostic tests are in widespread use today but are challenging to scale up for any kind of mass testing because they require trained personnel to run them. Companies, like OraSure Technologies, are currently developing these tests using oral fluid samples and say they hope they’ll produce a result in 20 minutes. 

Antigen tests, if they work, could be cheaply manufactured and administered at home. It’s unclear how much these tests would cost, but David R. Walt, a diagnostics expert from Harvard Medical School and Brigham and Women’s Hospital, doesn’t expect the price tag to be higher than $10 per test. Some employers and insurers will likely cover the cost. 

“There will never be the ability on a [PCR] test to do 300 million tests a day, or to test everybody before they go to work or to school,” Deborah Birx, who leads the White House Coronavirus Task Force, said on April 17. “But there might be with the antigen test.”

If antigen tests meet the bar for accuracy, doctors envision a future where Americans self-administer tests to get a quick yes or no on whether to go back to work or return to school. Those results could also be wirelessly communicated to public health departments for the purposes of surveillance. At-home testing is so important, they say, because relying on doctors or other medical professionals would create delays and sap limited supplies of protective personal equipment. 

“Four or six months down the road, I suspect we’ll have pretty good test strips that people will be able to buy like a pack and test themselves every few days or if they’re considering going back to school or work,” said Dr. Walt. “You could imagine going to work for four days, breaking to work from home for seven, and socially distancing in between or controlling your social interactions,” he continued. “Then you test yourself at home the day before you go back (to work) again.”

Dr. Walt says that there might be a path to bring these tests to market faster, but it would require a coordinated national strategy and “some sort of rigorous validation with a dedicated testing facility.” Otherwise, he expects, it could take “four to six months” for these kinds of tests to get a green light.

Challenges that lie ahead

But there are still many unknowns when it comes to the reliability of these tests. Antigen tests are known to work better with a bacterial disease, such as strep. But there are challenges with viruses, and the effectiveness might vary from person to person. 

Four or six months down the road, I suspect we’ll have pretty good test strips that people will be able to buy like a pack and test themselves every few days or if they’re considering going back to school or work.

Dr. David R. Walt

diagnostics expert, Harvard Medical School and Brigham and Women’s Hospital

For that reason, medical experts expect that antigen tests, if approved, will be used first as a “point of care” test, meaning they’ll be administered while a patient is receiving care from a medical professional. Dr. Walt believes this would represent a promising step forward, once these tests are broadly distributed to medical clinics and urgent care centers. Consumers could drive up for a test and get the result by the time they get home, he suggests. 

That could be coming sooner rather than later. “There are at least two home tests that are going through emergency use approval right now, but my strong sense is that if they get approved, it’ll be for point-of-care use,” said Michael Pellini, an investor with Section 32 and a longtime diagnostics executive. Pellini could not disclose the names of the test makers until the details were made public. 

“From there the companies can work closely with regulators to find a path to true home-use testing,” he continued. 

Antibody tests, which look for signs of a previous infection from the virus, are another option for at-home testing. But the FDA has come under fire from scientists for rapidly approving coronavirus antibody tests without providing sufficient evidence that they are accurate. Now the agency is currently reviewing the data to determine whether these tests do indeed meet the quality standard. 

There’s also some promise in using CRISPR, a gene-editing technique, to diagnose the novel coronavirus as quickly as a pregnancy test. Such a test could cost around $6, if approved, and researchers are working on the device at the Broad Institute in Cambridge and other labs. It’s still unclear how well these tests will perform in real-world settings, especially when compared to the standard PCR tests. 

Many doctors believe that these tests are more likely to be useful in helping public health departments understand the extent of the virus’ spread in communities, and not to determine whether it’s safe for people to return to work or stop social distancing. Dr. Stephen Hahn, the FDA commissioner, has warned that the antibody tests aren’t enough to make a determination about sending someone back to work. 

“Even once we understand the sensitivity and specificity,” says Dr. Pellini, “we still then must understand what it means in terms for the patients’ immunity.” 

But in Pellini’s view, these open questions can be answered with “strong clinical studies.” 

Mass testing can be deployed with a “coherent, national strategy,” he adds.

Now is the time, Dr. Pellini urges. Covid-19 might be widespread in some communities, but testing is still a major part of almost every think tank and consulting firm’s strategy to get Americans back to their lives. And not just testing those who are symptomatic, but testing everyone — and repeatedly. Millions of these tests will be required, Pellini suggests, to safely get Americans back to their normal lives. 

What Pellini is seeing instead is a lot of promising — but somewhat independent — efforts under way, which are being championed by a company or academic medical center. 

“They are basic questions that have to be answered with thoughtful and standardized clinical studies, all of which could be performed in a very short time period if we truly wanted to do that as a nation,” he said. “There’s no magic here.”

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