Public-health experts have found evidence that small household gatherings are starting to drive the growth in U.S. COVID-19 cases—and have warned that Thanksgiving could send the number of cases spiraling. U.S. Centers for Disease Control and Prevention Director Robert Redfield held a call with the nation’s governors on Tuesday. CNN obtained audio of the chat, in which Redfield said: “What we’re seeing as the increasing threat right now is actually acquisition of infection through small household gatherings... Particularly with Thanksgiving coming up, we think it’s really important to stress the vigilance of these continued mitigation steps in the household setting.” Meanwhile, a Sweet 16 party at a Long Island, New York, catering hall has been connected to 37 confirmed cases, according to reports, and has caused some 270 people to quarantine.