President Trump defended his assertion that the novel coronavirus would “disappear” with or without a vaccine on Tuesday, saying the United States would develop what he called “herd mentality.”

“With time it goes away,” Trump said during an ABC News town hall in Pennsylvania when pressed by host George Stephanopoulos on his public comments about the virus. “You’ll develop, you’ll develop herd — like a herd mentality. It’s going to be, it’s going to be herd-developed, and that’s going to happen. That will all happen. But with a vaccine, I think it will go away very quickly.”

Trump appeared to mistake “herd mentality” for “herd immunity,” which occurs when enough individuals develop immunity to prevent the spread of a disease.