Herd immunity is the idea that, you know someone who has been vaccinated, if they got the infection, they can't pass it on to people. And i guess one of the goals of vaccine drives like were part of in canhove a really unprecedentedly global scale right now,. Is that something that looks like it's likely in the context of saskovti? That scenario very much depends on how well the vaccines perform at not just preventing disease, but at preventing infectiousness. I mean, we've got these new variants that are coming up that might effect that, but i think it's still very much yet to be seen, really.