Here’s what you need to know about rapid, at-home COVID tests

This Wednesday, Feb. 3, 2021 file photo shows a BinaxNOW rapid COVID-19 test made by Abbott Laboratories, in Tacoma, Wash.Ted S. Warren/Associated Press

Rapid at-home coronavirus tests are in the news, with the Biden administration’s announcement last week that the government would make a massive purchase of the tests in hopes of addressing ongoing shortages.

Here’s a roundup, compiled from Globe wire service and major media reports, of what you need to know about the tests.

What did the Biden administration announce?

Jeff Zients, the White House coronavirus response coordinator, announced Wednesday that the government would buy an additional $1 billion worth of the tests. By December, he said, the number of the tests available to Americans is expected to quadruple, to more than 200 million a month. It’s part of the administration’s effort to “ensure that every American, no matter their income level or ZIP code, can access accurate, convenient, and affordable testing,” he said.

What is the CDC’s current recommendation on rapid, at-home tests?

The Centers for Disease Control and Prevention website says that if you have COVID-19 symptoms or have been exposed to someone with confirmed or suspected COVID-19, you should be tested, whether you’re unvaccinated or vaccinated. And if you can’t get tested by a health care provider, you can consider rapid, at-home testing, the agency says.

After testing, you should discuss the results with your health care provider, the agency says. If the result is positive, you can discuss further PCR laboratory testing for confirmation. You should stay in touch with your provider during your illness (as well as isolate yourself and notify close contacts). If your illness becomes severe, you should seek medical attention.

If the test is negative, your “current illness is probably not COVID-19,” CDC says. The agency notes, however, that a number of self-tests are designed to be taken multiple times over several days to ensure accuracy and asks people to make sure to follow the directions on those tests.

The Food and Drug Administration also recommends that if you test negative and still have COVID-like symptoms, you should check in with your health care provider.

Could there be even broader use?

Experts envision a world where the tests are used regularly by a large segment of the population to test themselves even when they don’t feel sick, allowing early detection of the disease, which would allow people to isolate and stop spreading the virus. The experts have pointed to the efforts of countries such as Britain, where free at-home tests are made available so that everyone can be tested twice a week.

“Imagine if every family was given twice-weekly, at-home tests to take before kids go to school and parents head to work. Imagine, too, if it becomes the norm for friends and family to take rapid tests before getting together for weddings, birthday parties, and even casual dinners and happy hours. When implemented together with vaccine requirements, regular testing can replace the need for masking and distancing in schools, offices and social settings,” Dr. Leana Wen, a public health professor at George Washington University, wrote in an opinion piece last week in the Washington Post.

How much do the tests cost?

Dr. Michael Mina, an epidemiologist at the Harvard T.H. Chan School of Public Health who has been an outspoken advocate since early in the pandemic for rapid at-home tests, said in an opinion piece with a colleague in The New York Times that tests can cost from $7 to $50 — when they should be free.

He told reporters in a media briefing Wednesday: “Individuals should not be on the hook for paying for them. The government should be subsidizing, which is what we see in other developed countries. Most of our peer nations are barely charging or giving these out for free to individuals, and that’s smart public health.”

Zients said a new test authorized by the FDA from Acon Laboratories will likely cost less than $10. He said the administration is counting on market forces to bring down prices.

The government’s commitment to buy the tests, which followed a $2 billion investment announced in September, was intended to give test manufacturers the confidence to increase production and “as we get more and more tests approved and manufacturing ramps up, pricing should come down as economies of scale are achieved and competition kicks in,” Zients said.

Has there been a shortage of these tests?

The action on tests follows reports from around the country of people having difficulty buying at-home tests, with demand up from parents purchasing them for children who are going to school and employees returning to workplaces, National Public Radio reported.

Are the tests accurate?

Most of the rapid at-home tests authorized by the FDA are antigen tests. Antigen tests are less sensitive than the gold standard PCR tests, sometimes missing people who are infected with the virus. Concerns about the tests have been heightened recently by a recall of tests made by the company Ellume. But the tests are generally excellent at flagging people who have high viral loads — and who are thus most likely to be actively transmitting the virus, experts say. And using the tests repeatedly can compensate for their lower sensitivity.

Mina has also pointed out numerous times that any test has a better sensitivity than no test at all, tweeting this week, “A test not performed has 0% sensitivity.”

The latest action by the Biden administration has been hailed by a chorus of public health experts. “We wasted all of last year when rapid tests would have saved thousands of lives,” tweeted Dr. Ashish Jha, dean of the Brown University School of Public Health. “They’re still enormously important. We need to make cheap antigen tests widely available.”

Material from Globe wire services was used in this report.