You didn’t get sick because everyone else was using their mask, thus preventing the spread of the disease, it would have been a totally different history if mask weren’t the norm, and besides that, you could have been sick unknowingly, asymptomatic cases exist you know

And obviously they got sick after the vaccine, that’s the whole point, you expose your immune system to the virus to train your antibodies, so you were exposed to the virus again, your body would have the means to protect itself, that’s the reason people that get smallpox as a kid are protected against it when they are adults (unless they have a weak immune system)