US Centers for Disease Control and Prevention Director Dr. Rochelle Walensky explained the agency's stance on rapid tests on CNN’s New Day Wednesday. Walensky said the CDC does not recommend rapid tests for ending Covid-19 isolation because they don’t know how they perform or predict how transmissible people are at the end of infection.
“We do, just to be clear, recommend having a rapid test during your period of quarantine after you’ve been exposed,” Walensky said when asked why the CDC didn’t recommend taking a rapid test after the five days of isolation. “We opted not to have the rapid test for isolation because we actually don’t know how our rapid tests perform and how well they predict whether you’re transmissible during the end of disease.”
The US Food and Drug Administration has not authorized them for that use, she said, and it is not known how they perform.
“So what we said was, well, if you got a rapid test at five days and it was negative, we weren’t convinced that you weren’t still transmissible,” she said. “We didn’t want to leave a false sense of security, we still wanted you to wear the mask. And if it was positive, we still know the maximum amount of transmission was behind you, we still wanted you to wear a mask and given that we were not going to change our recommendations based on the result of that rapid test, we opted not to include it.”
Asked why health care workers need a negative test just a few days ago, according to CDC guidance, but the general public doesn’t, Walensky said that infection control recommendations in health care workplaces are “always more stringent” than for the general population.
She also said that the decision had nothing to do with shortages of rapid tests, saying “this decision really from an isolation standpoint had everything to do with the fact that we wouldn’t change our guidance based on the result of that rapid test. And you know that it didn’t have anything to do with any shortage at all, because we recommend rapid tests for those in quarantine.”
You can read more about the CDC's updated isolation guidelines here.