These kinds of "breakthrough infections" are usually mild or asymptomatic. Relaxed restrictions and the spread of variants may have increased the risk of an outbreak. The Yankees provided an important lesson in epidemiology this week: Even if you've been fully vaccinated, it's still possible to get the coronavirus. As of Thursday, three of the team's coaches, four members of its support staff, and one player — shortstop Gleyber Torres — have tested positive for COVID-19, though they got vaccinated several weeks ago. The Yankees players and coaches all received Johnson & Johnson's single-d...