If someone had suggested five months ago that we would be seeing more than 3 million cases and 135,000 COVID-19 deaths in the U.S. by mid-July, I wouldn’t have believed it. But now it’s distinctly possible that, five months from now, half of all Americans could have been infected with SARS-CoV-2, and more than 800,000 Americans may die in this extraordinary outbreak. That is what many of our most prominent public-health experts now expect.