Part of my take on COVID-19 vaccines is going to be: I think it's going to take a little longer than we think; I think it's going to probably not be quite as safe as we think, meaning not something you just want to indiscriminately give to everybody—in other words, like any vaccine, I think it's going to have some risk; and it's certainly possible that at least some of those vaccines, potentially really efficacious ones, may come with side effects that are undesirable, and therefore, we'll have to think about who gets them.