While I'm aware of how common it is to completely disregard those of us older adults (which unfortunately are all lumped into the same elderly category as "frail) who happen to be not only extremely active but one hell of a lot more healthy than our obese fellow citizens in their thirties, you ignore that category completely as though we don't exist. Look, everyone does that. However there is a good number of those of us whose immune systems aren't compromised as those younger folks who eat badly, eschew exercise and have lousy habits that we don't share. As an avid adventure traveler, life long exerciser and reader of Outside for whom you also write, I find it unfortunate that no mention at all is given to the subset that we inhabit. You can't mention all subsets as there are plenty. But lumping ALL folks over 65, and I am 67, into the frail category is not only monumentally foolish, but it ignores that there are plenty of us who are incredibly healthy. And whose immune systems are in one heck of a lot better shape than thirty somethings whose health is badly compromised by lousy lifestyle habits we don't share. If you look at what builds a powerful immune system: exercise, good food, good attitude and lifelong good habits, we've got a better shot at having a vaccine work for us than folks who succumbed to crap food and the remote as their exercise program early on. Just saying.