Vaccine push raises risk virus will linger

The U.S. strategy to rely on vaccines and treatments, rather than emphasizing social distancing, masks and testing nationwide, threatens to delay the return to normal life for Americans…

But ending the crisis won’t be quick or easy. Vaccines may initially slow deaths among the vulnerable, such as those with chronic conditions. But the logistical, production and public education challenges of immunizing 60% to 70% of national populations — the level the World Health Organization says is needed to achieve herd immunity — will be a time-consuming process. The world will still need masks, social distancing, widespread testing and effective new therapies to keep the virus at bay, public-health specialists say.

A vaccine isn’t “a magic wand,” said Marie-Paule Kieny, a research director at the French health-science institute Inserm and a former World Health Organization official. “It will not be a quick fix, even if it’s effective.” Read more from Naomi Kresge, James Paton and John Lauerman.