reporting, sanjay, on why it's taking so much longer for children than it is adults? >> yeah. one big thing and maybe this is an obvious thing is that the fda cannot really act on this until all the data is submitted, so what we're learning it's a bit of a circular thing. the companies, they say here's the data that we have and the fda says we need more data. not surprising that it's kids because kids are less likely to get sick and the bar has to be higher. they want six months of safety data, john, as opposed to two months as it was more adults at the end of last year so it's just going to take longer. when you look at the timeline. you can see it there. the data for pfizer expected in september. when we looked at previous data submissions and the time course of how it took to get to eua, maybe a couple of weeks after that. it could go that quickly. we'll see, but sort of projections are sometime late september, early october, sometime in the fall. >> parents are getting anxious to say the least. >> i know. >> sanjay, we're learning how many people in the u.s. are estimated to have antibodies to covid-19. that includes i imagine vaccines