In little more than a week, Robert Wachter, chair of the department of medicine at the University of California, San Francisco, says his assessment of the risk posed by the Delta variant has changed—and he has changed his behavior accordingly.

Dr. Wachter, who is 63, says he still watches “Ted Lasso” unmasked when his adult son comes over. He has stopped his monthly poker games with eight friends, even though all are vaccinated. The group is big, he reasons, and one member is immunocompromised. Dr. Wachter’s age puts him at higher risk, and he says he worries his vaccine protection may have waned somewhat because he was inoculated about seven months ago.

Double-masking is now the rule when he goes to the grocery store, and he no longer eats indoors at restaurants. “The right way to approach this is as if it were a new virus and question all your assumptions,” he says…

All said they are wearing masks again in crowded indoor public places. They mostly wear N95s in higher-risk settings, like with patients or on planes, and double up with cloth and surgical masks in less risky situations. Most have stopped dining indoors. They are still largely comfortable taking off masks in groups of friends and family when they are sure everyone present is vaccinated, depending on the size of the group.