Two weeks after the U.S. Centers for Disease Control and Prevention took down a statement about airborne transmission of the coronavirus, the agency Monday replaced it with language citing new evidence that the virus can spread beyond 6 feet (1.8 meters) 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 CDC 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 CDC did not endorse their use by the public until April, and the WHO did not do so till June.