If a theme runs through the books and articles I’ve written over the past 40 years, it’s a fascination with what scientists have learned about the human body. A long career spent explaining biomedical research has led me to a deep respect for the scientific process. Despite its occasional missteps and self-corrections, I believe it ultimately moves us toward a clearer understanding of the world and how to thrive in it.
So as scientists first scrambled to figure out the never-before-seen coronavirus, I was primed to follow their advice about how to keep safe, based on the hypothesis that the virus was transmitted mostly by droplets from coughs and sneezes lingering on surfaces. I dutifully wiped down countertops, refrained from touching my face, and washed my hands so emphatically that the little diamond in my wedding ring shone like never before.
And then, about two and a half weeks after my city, New York, shut down restaurants, Broadway plays, and the largest public school system in the country, scientists switched to a different message—that everyone should wear a mask. This was a startling about-face. The initial advice, confidently delivered, had been not to wear a mask, unless you were a frontline health-care worker. The revision was largely based on a new hypothesis, that the coronavirus spread mostly through the air. (See where coronavirus casese are growing and declining in the U.S.)