We are in a pandemic and there are epidemiologic principles that will hold true throughout. With each case of Covid passed from one person to another, a new copy of the virus is made. Imagine that the copies are being made by hand, by a scribe or monk in medieval times. Small errors can be made, a misplaced comma, an E replaced with an I. With each error comes the possibility that the new copy will have a “fitness advantage” making it easier to transmit. When this happens, whichever copy of the virus is the best at transmitting, will become the dominant variant. Sometimes the illness from the variant is similar to the original virus, sometimes it is more deadly, or harder to accurately test for, or harder to treat, evading our medications and therapies. When the virus is allowed to replicate and infect people, it poses a risk for all. It poses a risk for the unvaccinated in that they are not protected against any type of Covid. And it poses a risk for the vaccinated in that a new variant which is not covered by the vaccine could be created.