A passenger at a departure gate at Vnukovo International Airport in Moscow, Russia. | Sergei KarpukhinTASS via Getty Images

The confusing WHO remark and walk-back, explained.

For months now, it’s been widely accepted that many people infected with the novel coronavirus experience few if any symptoms but can still potentially spread the virus to others. Exactly how many of these people without symptoms are “silent spreaders” has been a mystery.

Despite the mystery, the public health message has been clear: We should behave as though we or anyone else could be a silent spreader. We should take precautions like wearing face masks, avoiding crowds, and maintaining physical distancing.

Yet that conventional wisdom seemed to be challenged this week when Maria Van Kerkhove, an infectious disease epidemiologist at Institut Pasteur’s Center for Global Health and a technical consultant for the World Health Organization (WHO),