a true exposure, you can come in, test, as long as you're negative, you're not endangering anyone, come in, do your in-person learning, and stay. then after five days test again. this has been used in europe, in multiple states around the country, and if it becomes standard, we'll have less kids out of school. >> big picture, the question here really is about risk reduction as opposed to risk elimi elimination. for folks who don't know, you run an hiv-aids clinic in san francisco, very different diseases here, but tell us what lessons you've learned about risk reduction as an approach as opposed to risk elimination as it relates to schools and covid. >> yeah, so, you know, this was also a prolonged infection. it turns out covid was much longer than we thought it would be. the idea is that you take people's needs into account, harm reduction, even trying to