israel and the considerations that are being made there as well. i spoke to some friends that live in israel right now, their fourth vaccine dose already scheduled for february. there is testing going on already in israel when it comes to that fourth vaccine dose. is it too soon? give me your reaction to this. >> well, it strikes me as a little too soon, yasmin. you know, i think there is some benefit here, in that we will gather some information from the israeli experience, as we did with our third dose and booster shots. but the truth is that in this country, we're still at a place where only a third of americans have received a third dose. it's far too early for us to be talking about a fourth dose in what looks like an increasingly small number of people who are actually getting boosted as all. i think if we're really going to prevent serious illness, now's the time to focus on the third dose to really rye to prevent the increase in significant illness that's going to put people in the hospital. but i don't think we're at a place where we immediate to be discussing a fourth dose seriously just yet.