QDEL QuidelOrtho Corporation

By Brianna Abbott 

The U.S. Food and Drug Administration authorized the first Covid-19 tests for repeated, frequent use by consumers at home to screen for infections even if they don't have symptoms.

The FDA late Wednesday gave the green light to three tests that are meant to be used frequently or multiple times over a few days -- called serial tests. Consumers will be able to buy two of them over the counter without a prescription; the other, for use in such places as schools and doctor's offices, requires a prescription. The FDA had previously authorized them for use among people with symptoms.

For almost a year, some U.S. public-health authorities have called for rapid Covid-19 tests that can quickly and frequently screen for the virus to help control the spread of the infection among people without symptoms. The FDA has already cleared a handful of tests that consumers can purchase over the counter and use at home. But they aren't designated as serial tests and aren't yet widely accessible.

Wednesday's authorizations, awarded to companies with bulk manufacturing power, add to the tests that can be purchased over the counter among people without symptoms if they are used repeatedly, potentially enabling rapid, at-home testing to become more widely accessible and affordable.

"It's putting control into the hands of Americans directly," said Mara Aspinall, co-founder of the Biomedical Diagnostics program at Arizona State University. "This is a step forward. The FDA has been saying that they want to encourage more at-home tests. This is taking those words and making them very real."

The three tests search for pieces of virus protein, called antigens, to help determine whether someone is infected. They were developed by Quidel Corp., Abbott Laboratories and Becton, Dickinson & Co.

The FDA authorized the Quidel QuickVue and the Abbott BinaxNOW to be purchased over the counter without a prescription when used as a serial test. The agency cleared the BD Veritor for serial testing in settings such as doctor's offices, schools and nursing homes with a prescription.

The new clearances come on the heels of guidance the FDA released for test developers on March 16 that provided a potential pathway for companies to seek emergency-use authorization for a serial test.

In general, rapid antigen tests tend to be less precise than molecular tests performed in a laboratory and sometimes require a follow-up test, but they can identify cases among people who have a lot of virus in their systems and are most contagious. Studies also suggest that testing frequency can make up for a lower-precision test.

The benefit of frequent, repeat testing with a serial test is that an infection that might be missed or is too early to be caught with the first test could be captured with the second a day or so later, public health authorities say.

"If someone has been exposed to Covid and they become positive, there's a lag time when they don't have a lot of virus" and might not test positive on an antigen test, said Mary Rodgers, a principal scientist in Abbott's diagnostic business. "If you are testing twice, then you have a better chance of having at least one test in the peak of that bell curve when someone is most contagious."

Abbott plans to sell the tests in a pack of two and aims to get the tests on store shelves within weeks, a company spokeswoman said.

Also on Wednesday, the National Institutes of Health and the Centers for Disease Control and Prevention launched an initiative to offer a month-long supply of the Quidel rapid antigen test to as many as 160,000 people in two communities, to determine whether frequent screening can help reduce community transmission.

Write to Brianna Abbott at brianna.abbott@wsj.com

(END) Dow Jones Newswires

April 01, 2021 13:16 ET (17:16 GMT)

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