People Exposed to Covid May Need to Take as Many as Three At-Home Tests, F.D.A. Says

The FDA said on Thursday that people who are using at- home Covid-19 tests should take at least three tests in a 48 hour period to reduce their chance of getting an infectious disease.

At least two tests should be taken by people with Covid-19 symptoms.

As the highly transmissible BA.5 subvariant of Omicron continues to spread, the Centers for Disease Control and Prevention has changed its recommendation for routine testing.

Many people have reported that at home tests failed to detect their infections, but studies show that rapid antigen tests are as good at detecting Omicron as they are at detecting Delta.

Rapid antigen tests, which are less sensitive than P.C.R. tests, are most likely to detect the coronaviruses when people take them repeatedly over the course of several days, according to experts.

The need for additional testing over a longer period of time is emphasized by the new recommendations.

The director of the agency's Center for Devices said that the F.D.A.'s new recommendations for at- home Covid-19 antigen tests emphasize the importance of repeat testing after a negative test result.

The results of a new national study are the basis for the new guidance. 154 people who tested positive for the virus using P.C.R. tests between October and February of this year were the focus of the study.

There were two tests that detected 93 percent of infections. The testing pattern found 63 percent of infections in people who weren't sick.

The tests caught most of the infections when people took three tests in a row.

The results suggest thatserial testing with antigen tests is still a useful way to detect infections.

The F.D.A. said that people who have received two or three negative results on at- home tests can still take a more sensitive P.C.R. test.

The agency said that people who test positive should follow the guidelines of the C.D.C.

The C.D.C. still recommends that people who test positive for the coronaviruses at home for at least 5 days.

The F.D.A said that people don't need to use the same brand of test multiple times.

The agency said to have several tests on hand so you can test more than one time.