covid-19. but for johnson & johnson soon after vaccination it's 72%. that's still a good number, but it's not as good as moderna and pfizer. that's why he said that. also at this meeting we're expected to hear a discussion about mixing and matching. for example, if you got johnson & johnson the first time around, say six months ago, could you now get a pfizer or moderna booster? it's just a discussion. no decisions will be made. what's interesting is that a study, relatively small study of about 450 people, it actually showed that folk who is got johnson & johnson the first time, they were actually better off if their booster were pfizer or moderna. kate? >> fascinating. thank you, elizabeth. we'll watch this. joining me right now in the meantime, cnn medical analyst dr. lena wen, former health commissioner for city of baltimore. we know pfizer's booster got the green light. moderna is the same, held there. is it a given in your mind that johnson & johnson's booster will