Gedalia society using detailed surveys and an actual understanding of how statistics work, estimated 60-70% infected (not exposure).
In my circle of friends (similar age group to Yehuda57) I haven't found anyone else who didn't have clear symptoms before purim. So I'm also the only guy in my shul with a mask (or was through the summer, will be next week). And yes, that is the more uncomfortable part. Are surgical masks less obtrusive, or black cotton?