Until a vaccine or another protective measure emerges, there is no scenario, epidemiologists agreed, in which it is safe for that many people to suddenly come out of hiding. If Americans pour back out in force, all will appear quiet for perhaps three weeks.
Then the emergency rooms will get busy again.
“There’s this magical thinking saying, ‘We’re all going to hunker down for a while and then the vaccine we need will be available,’” said Dr. Peter J. Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine.
In his wildly popular March 19 article in Medium, “Coronavirus: The Hammer and the Dance,” Tomas Pueyo correctly predicted the national lockdown, which he called the hammer, and said it would lead to a new phase, which he called the dance, in which essential parts of the economy could reopen, including some schools and some factories with skeleton crews.
Every epidemiological model envisions something like the dance. Each assumes the virus will blossom every time too many hosts emerge and force another lockdown. Then the cycle repeats. On the models, the curves of rising and falling deaths resemble a row of shark teeth.
Surges are inevitable, the models predict, even when stadiums, churches, theaters, bars and restaurants remain closed, all travelers from abroad are quarantined for 14 days, and domestic travel is tightly restricted to prevent high-intensity areas from reinfecting low-intensity ones.
The tighter the restrictions, experts say, the fewer the deaths and the longer the periods between lockdowns. Most models assume states will eventually do widespread temperature checks, rapid testing and contact tracing, as is routine in Asia.
Even the “Opening Up America Again” guidelines Mr. Trump issued on Thursday have three levels of social distancing, and recommend that vulnerable Americans stay hidden. The plan endorses testing, isolation and contact tracing — but does not specify how these measures will be paid for, or how long it will take to put them in place.