Financial markets paused their slide Thursday, but no one should think this rolling economic calamity is over. If this government-ordered shutdown continues for much more than another week or two, the human cost of job losses and bankruptcies will exceed what most Americans imagine. This won’t be popular to read in some quarters, but federal and state officials need to start adjusting their anti-virus strategy now to avoid an economic recession that will dwarf the harm from 2008-2009.

The vast social-distancing project of...