"Most holiday events revolve around food, so you aren’t masking up. Even if people do wear masks, they have to take them off to eat."

Carrie Horn, chief medical officer at National Jewish Health, an academic medical center and respiratory hospital based in Denver, commenting to Bloomberg for its recent report, “Covid Cases Near 10 Million in U.S., No Slowdown in Sight.”  Horn noted that when just one in 50 people were infected, small gatherings were less likely to include someone who might have been unknowingly infected. Lowering that to about one in 20 people significantly raises the risk.