WASHINGTON (AP) — In a matter of days, millions of Americans have seen their lives upended by measures to curb the spread of the new coronavirus.

Normally bustling streets are deserted as families hunker down in their homes. Many of those who do venture out try to stay a safe distance from anyone they encounter, even as they line up to buy now-precious commodities like hand sanitizer. Parents juggle childcare as schools close, perhaps for the rest of the school year. And restaurants and bars sit empty as more and more convert to delivery-only options.

How long will this last? Scientists say th...