Thirteen days ago, David Lat lay on a stark white hospital bed in Manhattan, getting oxygen 24 hours a day because his breathing had grown so labored. And he dared not look ahead too much, he said, as he faced up to his battle with a severe COVID-19 infection.

“I don’t know that I’m getting any worse,” he said by cellphone on March 18, speaking about his illness. “And at this point,” he said, “I’ll take it.”