The U.S. Centers for Disease Control and Prevention said tiny particles that linger in the air can spread the coronavirus, revising its guidelines on the matter just a few weeks after the health agency had acknowledged a role for the particles and then abruptly removed it. The guidelines on how the coronavirus spreads were initially updated last month to acknowledge a role, and possibly the primary one, played by tiny aerosol particles in spreading the virus. But the agency removed the changes only days later, saying a draft version of the proposed changes had been posted in error. In its...