By Apoorva Mandavilli in the NYT.
Ed note: We should be particularly aware in elevators that we cannot adequately socially distance. Thus, elevator conversation should be kept to a minimum despite how tempting it is to meet and greet.
Two weeks after the Centers for Disease Control and Prevention took down a statement about airborne transmission of the coronavirus, the agency on Monday replaced it with language citing new evidence that the virus can spread beyond six feet indoors.
“These transmissions occurred within enclosed spaces that had inadequate ventilation,” the new guidance said. “Sometimes the infected person was breathing heavily, for example while singing or exercising.”
The incident was only the latest in a series of slow and often puzzling scientific judgments by the C.D.C. and by the World Health Organization since the start of the pandemic. Despite evidence that use of face coverings can help cut down on viral spread, for example, the C.D.C. did not endorse their use by the public until April, and the W.H.O. did not do so till June.
Regarding aerosols — tiny airborne particles — the C.D.C. lagged behind even the W.H.O. In July, 239 experts who study aerosols called on the W.H.O. to acknowledge that the coronavirus can be transmitted by air in any indoor setting and not just after certain medical procedures, as the organization had claimed.
Notably, the C.D.C.’s new guidance softens a previous statement referring to the coronavirus as “an airborne virus,” a term that may have required hospitals to treat infected patients in specialized rooms and health care workers to wear N95 masks anywhere in a hospital.
The new advice instead says the virus can “sometimes be spread by airborne transmission” and can be spread by both larger droplets and smaller aerosols released when people “cough, sneeze, sing, talk, or breathe.”
But while the virus can be airborne under some circumstances, it is not the primary way the virus spreads, the C.D.C. said.
“I’m a little concerned that they still distinguish between close contact and airborne transmission, implying that airborne transmission only matters beyond six feet,” said Linsey Marr, an expert in airborne transmission of viruses at Virginia Tech in Blacksburg, Va. “Airborne transmission also occurs at close contact and is probably more important than the spray of large droplets.”
The revisions arrived as President Trump received treatment at Walter Reed National Military Medical Center in Bethesda, Md., for what may be a severe case of Covid-19, the illness caused by the coronavirus. (Mr. Trump left the hospital on Monday evening.)
The administration is contending with a rising number of such infections among Mr. Trump’s inner circle. Kayleigh McEnany, the president’s chief spokeswoman, announced on Monday morning that she had tested positive for the coronavirus, the latest in a string of political figures heading into self-quarantine following what may have been a so-called superspreader event at the White House earlier this month.