@keks partially masking, in particular in crowded/badly ventilated places as you probably did, massively reduces the overall intake of pathogens. Congrats!
I regularly got #FOSDEM flu and/or #Chaosseuche and... nothing... since I started masking there.
In fairness, I did catch #COVID at #KubeCon #Japan, but I was next to two coworkers who I knew were sickly for several days in a badly ventilated venue. I was stupid, and I learned from it.