Jan 15, 2022 - Health

Concerns grow over CDC's isolation guidelines

Illustration of three figures indicating how to use a rapid COVID test. 

Illustration: Aïda Amer/Axios

New data suggests that people with the Omicron variant frequently stay infectious for longer than five days, raising concerns about the CDC's updated isolation guidelines.

Why it matters: Experts say the issue could be resolved by using rapid tests to determine whether it is safe to exit isolation, but the CDC has not recommended a negative test as a condition to end isolation.

Driving the news: A new study of NBA players and staff — which has yet to be peer-reviewed — found that a large percentage of Omicron-infected people still had viral loads over a certain threshold five days after their first positive test.

  • The study used this threshold as a proxy for infectiousness and for triggering a positive antigen test.
  • That suggests that a sizable portion of Omicron infections will still be infectious at day five.

What they're saying: "Main take-away = ending isolation at day 5 should include a negative rapid antigen test. Otherwise isolation needs to be extended," tweeted Nathan Grubaugh, a Yale professor and an author of the study.

  • "Why do all of the work to identify infections if we are going to just let them go back to work while still potentially infectious?"

The big picture: The data adds to growing anecdotal evidence — in the form of positive antigen tests past the recommended isolation period — that there's no guarantee that someone isn't infectious after five days.

  • The CDC does recommend that people who leave isolation after five days wear a mask around others.

Yes, but: There's at least one hugely practical argument for allowing people to leave isolation (with a mask) after five days: So many Americans are infected right now that it threatens basic societal functions for them all to stay home longer.

  • And there's a shortage of rapid tests, given the surge of demand for them, meaning that recommending people use them to leave isolation may fall flat if there aren't any tests to be found.
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