It’s surprising, but experts agree: The tens of thousands of people being vaccinated against the coronavirus right now may still be able to carry and transmit the SARS-CoV-2 virus to others, despite being well-protected against the symptoms of COVID-19 themselves. That means they must still wear masks and practice social distancing to protect those around them. “We still have yet to learn how much infectivity is impacted by vaccination, thereby producing protection for those I am in contact with, not just for myself, when I receive a vaccine,” says Dr. Janet Baseman, a public health expert at the University of...