Even if its not covid that makes plenty of sense, if you were masked for 1yr+ and didn't get sick then your immune system would be more susceptible to common colds and whatnot due to the lack of what would have previously been much more frequent exposure
I worked at a toy store once, got sick 3 times in the first 6 months, then basically never got sick at all for the next 4 yrs. Stopped working there and within a year was getting more regular colds again.
XI Wiki





