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CDC considering testing guidelines for the asymptomatic, Fauci says

The CDC is aware of the "pushback" after it shortened its isolation guidance, Dr. Anthony Fauci said.
Covid-19 testing site
A medical technician performs a nasal swab test on a cyclist at a Covid-19 testing site near All City Stadium in Denver on Thursday.David Zalubowski / AP

The Centers for Disease Control and Prevention is considering adding testing requirements to its new isolation guidelines for asymptomatic Covid-19 patients, Dr. Anthony Fauci said Sunday.

The CDC shortened its isolation recommendations from 10 days to five last week for people who have tested positive for Covid but show no symptoms. Fauci, President Joe Biden's chief medical adviser, said the agency is debating adding to its guidance.

"The CDC is very well aware that there has been some pushback about that," Fauci said Sunday on ABC News' "This Week." "Looking at it again, there may be an option in that, that testing could be a part of that."

It's unclear whether positive tests would require further isolation or whether asymptomatic patients would be free to move about as long as they're masked.

Just last week, Dr. Rochelle Walensky, the CDC's director, said new guidelines don’t require testing at the end of isolation because PCR tests for Covid can be positive for up to 12 weeks, long after people are no longer infectious.

“We also don’t know that antigen testing is a good indication of transmissibility at this stage of infection,” she said at a White House briefing. “On the other hand, we know that after five days, people are much less likely to transmit the virus and that masking further reduces the risk.”

The CDC’s decision to cut isolation time was met with pushback and confusion over the last week, as some health experts said it wasn’t based on science and could cause still-infectious asymptomatic people to transmit the coronavirus to others.

Fauci also defended the CDC's decision in an interview Tuesday on MSNBC's "All In with Chris Hayes," including the decision not to include testing. The new, shorter isolation guidance was a result of concern that the high transmission rate of the omicron variant of the virus could have a "negative impact on our ability to maintain the structure of society," Fauci said.

He told Hayes that the approval of tests didn't include whether a test could predict whether someone is infectious.

The CDC says a test's ability to predict infectiousness is "much, much more weighted towards the earlier first five days," Fauci said.

"Once you get into the latter part of that, the predictive value of that in telling you whether or not you're infective or not, there's no real data to say that. There's very little known about that," he said. "And that was the basis of the CDC decision."