When Will It Be Safe to Loosen Coronavirus Lockdowns?

Governments prepare for the long haul as authorities grapple with how much economic pain countries can endure.

As the new coronavirus spreads across the world, governments and scientists are bracing for a monthslong siege rather than a swift victory—one marked by shifting strategies and potentially prolonged economic disruption.

Sweeping restrictions and unprecedented lockdowns from New York and San Francisco to Milan, Paris, Manila and Kuala Lumpur, Malaysia, are expected to slow the spread of the disease, but they aren’t likely to halt the contagion altogether, public-health experts say. Places like...