Ronald Collman of the Perelman School of Medicine recommended wearing a mask indoors when near people from other households. "It is going to be the most effective way to lessen the likelihood of person-to-person transmission," he said. "This may be the season for small gatherings with your most intimate family members."

https://www.nbcnews.com/health/health-news/cdc-stumbles-again-mistakenly-posting-draft-guidance-airborne-covid-spread-n1240602 NBC News