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The Centers for Disease Control and Prevention, which quietly changed its guidance on coronavirus transmission through the air Friday, reversed field again Monday. Sort of. On Friday, the CDC posted an update on its website saying 6 feet may not be sufficient to keep people safe and that ventilation was key to easing transmission indoors. That determination could be crucial for schools where desks are now set up 6 feet apart. Offices, restaurants and even church services also could be affected by the change. (Bacon, 9/21)

"This was an error on the part of our agency and I apologize on behalf of the CDC," John Brooks, chief medical officer for the CDC's COVID-19 Emergency Response, during a call Monday with providers and state and local health officials. "We weren't ready to put it up." The agency's website now emphasizes the risk of close person-to-person contact, as it before the change Friday. That is "the main mode" of transmission, Brooks said. (Ehley, 9/21)

Experts with knowledge of the incident said on Monday that the latest reversal appeared to be a genuine mistake in the agency’s scientific review process, rather than the result of political meddling. Officials said the agency would soon publish revised guidance. ... Still, the reversal prompted rebukes from even the C.D.C.’s staunchest supporters. “It’s not something that instills a lot of confidence, right?” said Dr. Carlos del Rio, an infectious disease expert at Emory University. “It doesn’t help at all.” (Mandavilli, 9/21)

For a few days, researchers who have suspected aerosol transmission for months cheered the update as a long-overdue acknowledgment of accumulating evidence for how the virus transmits, particularly in indoor spaces. Now the page has reverted to what it said before — that the virus spreads between people in close contact through respiratory droplets. The page makes no mention of aerosol transmission. (Wamsley, 9/21)

It was the latest disorienting turn in a scientific debate with enormous public consequences for how we return to schools and offices. The debate is over whether the extreme infectiousness and tenacity of the coronavirus is due to its ability to spread well over six feet, especially indoors, in small particles that result from talking, shouting, singing or just breathing. Many experts outside the agency say the pathogen can waft over considerably longer distances to be inhaled into our respiratory systems, especially if we are indoors and air flow conditions are stagnant. (Guarino, Mooney and Elfrink, 9/21)

On Friday, the CDC updated its website to acknowledge that airborne transmission of the coronavirus beyond six feet may play a role in the COVID-19 pandemic, particularly indoors. The update was hailed by infectious disease experts interviewed by ABC as an overdue step. But on Monday morning, the agency took down that language, saying it was posted in "error." Despite the CDC guidance whiplash, experts say it's time to recognize that airborne transmission beyond six feet is possible -- while continuing to emphasize that close contact within six feet is still the main way the virus is transmitted. (Harrison and Salzman, 9/21)