doctor, thanks for joining. so when the fda advisory board meets tomorrow, they are going to have a lot to consider when it comes to these boosters. how do you see this playing out? >> well, i really don't know, don. i mean, it's interesting. before all these fda meetings in the past, we had a really good inclination of how it was going to turn out, you know, before the authorization of the vaccines and -- and all of that. but there's been a lot of back and forth. i mean, as you know, it made news when two senior vaccine scientists at the fda basically said they were going to leave. and it was subsequently found out it was over this issue of the boosters. so i think what's going to happen is there are going to be four big questions that are going to have to be addressed there. and we sort of laid 'em out here. you know, how much is immunity really waning? pfizer says the immunity wanes about 6% every two months but stays steady for severe illness. how severe are the breakthrough infections? i think this is a big one, don. i mean, you could have a totally asymptomatic breakthrough infection. you're surprised. i came back positive.