The Centers for Disease Control and Prevention’s newly updated COVID-19 guidelines don’t require a negative test to end isolation because PCR tests may return positive results for up to 12 weeks, Director Dr. Rochelle Walensky said Wednesday.
Walensky denied that the lack of a testing component had anything to do with supply issues involving rapid antigen tests in the US.
“This really had nothing to do with supply. It had everything to do with knowing what we would do with the information when we got it,” Walensky said on “CBS Mornings.”
Walensky said that PCR tests, which are more sensitive, would “not be viable” because they pick up traces of the virus for weeks.
“So we would have people in isolation for a very long time if we were relying on PCRs,” Walensky told “Good Morning America.”
As for using rapid antigen tests instead, Walensky said it’s unclear whether a negative result indicates that a person is no longer transmitting the virus.
“We know it performs really well during that period where you’re initially infected, but the FDA has not at all looked at whether … your positive antigen really does correlate with whether you’re transmissible or not,” she told “CBS Mornings.”
Under the new guidelines, those who test positive for COVID-19, but have no symptoms, can leave isolation after five days without testing again — but they should wear a mask for the next five days.
“What we do know is about 85 percent to 90 percent of viral transmission happens in those first five days, which is why we really want people to stay home during that period of time,” Walensky said. “And then mask for the rest of the time to capture that last 10 percent to 15 percent.”