What you are describing is, literally, conjecture.
I should've made it more clear.
It's not "just conjecture." I would classify it as "conjecture based on strong grounds", or something like that.
Basically, it's not just an educated guess. There is a very good reason to assume that if there has been a confirmed case of a very contagious variant in the region (and it's highly likely that there were a thousand at that point, because they don't test every person for variant), it would be strange if there were NOT a number of cases in Lakewood by now.
Yes, still conjecture, but not "just conjecture." Rather, "compelling conjecture."
Yes, I learned in a Brisker yeshiva.