to discuss the implications of this study, i am joined by skype from oxford, england, by philip goulder, a professor of pediatrics at oxford university, who led the research team. professor, what do these children have that's special? how is it they don't go from h.i.v. on aids? >> well, the interesting thing about these children is that, as you say, they don't progress to the disease through childhood. and children in general with h.i.v., something like 60% without treatment would die in the first two and a half years. so this is quite an unexpected finding. and we initially looked to see whether this was to do with the immune responses against the virus. and in fact, although they do make quite strong immune responses against the virus, this wasn't the reason they didn't progress. put the reason of that they, in spite of having a lot of virus on board, their immune activation levels are relatively low. so in some senses, they tend to ignore the virus, and as a result, they don't get any disease from it. >> sreenivasan: that's the opposite of what an adult body would do, right? i mean,