replicate. if you give them the opportunity to spread, you are giving them ample room to mutate. now not every mutation is going to wind up being functionally important, but if you let it mutate enough, sooner or later, you may get a constellation of mutations that will lead to variant that might evade the vaccine much more than the current delta is evading. it might be as replication competent but even more serious. which gets back again, fareed, to the recurrent theme. you can prevent that from happening by getting people vaccinated and not allowing the virus the freedom to freely go around, infect people, and mutate. we have the solution. we just need to implement it. >> let me ask you about an article you wrote. you co-authored about a year ago