“Viruses are sort of smart,” May Chu, a clinical professor of epidemiology at Colorado School of Public Health, told USA TODAY. “Our bodies offer the place where they replicate. And so if you don't let the virus into you, you aren't going to be contributing to the genetic growth of this virus. This is what you want to stop. Because the more people get infected, the more viruses grow, and the more chances of the genetic variant arising of deleterious effect.”