Good masks properly worn give some protection but it is only short term (best studies showed about 15-30 minutes in close contact with an infected person). No basic mask (N95) is going to protect you if you are sitting around for an hour or so, exposed to COVID.
Most kids had worthless paper masks, they did not wear them correctly and they were in close contact with each other for extended periods. It is not surprising that the masks were useless. Unfortunately at least some of these kids who got COVID in schools will have some permanent heart and lung damage from the toxic spike protein in the virus. The same spike protein is in the vaccine although it appears to be slightly less toxic, for whatever that is worth.
The spike protein in the vaccine is incredibly harmful.
It is more pervasive as it injected in the form of 40 TRILLION lipid nano-particles that can go anywhere in the body and turn any cell into a toxic spike protein factory.
From airborne bacteria, maybe. But virus sizes are many times smaller than the miniscule openings in the masks.