Some 50% of people who test positive for Covid-19 on a rapid test are likely no longer contagious, according to a study by the Journal of the American Medical Association.

Corona self-test

A woman is at home.

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A negative rapid test for Covid could be used to confirm an end to isolation, as 25% of study participants had a negative viral culture, suggesting they were no longer infectious.

Half of the participants who tested positive for the coronaviruses on a rapid test on day six of their infections also had a negative viral culture detected through a nasal and oral swab, according to a study.

The CDC suggested rapid tests on day 6 as an optional measure after shortening the required 10-day quark period from ten days to five, with five days of mask-wearing.

Imposing a universal negative rapid test requirement could extend isolation for those who are no longer infectious, though proper mask-wearing and avoiding crowded venues for 10 days is important for those who could still be infectious.

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During an increase in cases due to the highly transmissible omicron variant, the CDC has come under fire for shortening the quark period without a testing requirement. The CDC's guidance lacks clarity, as many experts say that antigen tests are a better measure of infectiousness for those who aresymptomatic, and should be used as an additional precautionary measure. According to the CDC, approximately 31% of people remain infectious five days after a positive Covid test. The agency believes that people are less likely to spread the disease after five days if they don't wear a mask.

President Joe Biden waited for a negative Covid test to end his isolation. After testing positive again for the coronaviruses last week after completing a five-day course of Paxlovid, Biden resumed isolation. Some research has found that people may be able to spread the coronaviruses to other people.

The CDC defended new isolation guidance.

Live updates on the coronaviruses.