There are many classes in Flatbush/BP currently home in quarantine - in BY of 18th Avenue, Torah V'Daas (possibly 2 grades), Lev BY, Ohr Shraga Veretzky, Toras Emes Kaminetz, Masores, Bnos Yaakov, and that's just the ones I've heard of.
Sadly, one of the aforementioned classes was not planning to quarantine despite a positive test for a student until a class father, who is an infectious disease doctor, got into a big argument with the administration and gave them no choice. Heard from said class father.
And this is before everyone gets together for unmasked RH/YK/Simchas Torah. Someone said this could end up giving us a new p'shat in Yom K-Purim, r"l.