natural immunity or vaccine-induced immunity. if i take my blood and try to neutralize the delta virus and the omicron virus, my blood is 40-50 times less able to newt rammize -- neutralize the omicron than the delta. so that just tells us we're going to need a higher level of immunity to protect ourselves, and that's why you're seeing breakthroughs in people. remember, the omicron variant, it's got a transmission advantage in a very unique population. the population are the previously infected and the previously immunized individuals. and it has that advantage over delta because it can escape the vaccine-induced or the natural immunity that's induced by infection to a much higher degree than delta. neil: dr. redfield, thank you very much. calming presence, sir, we appreciate that. we'll have a lot more after this >> thanks, neil.