Anecdotes don't show anything. You haven't controlled the variables.
So here are my anecdotes:
- I teach middle school. I usually start the year with about 40-50 boxes of tissues, and I always run out of tissues by February. We were face-to-face with masks all year. For the first time in 28 years, I ended the year with tissues left over. 26 boxes of them. While it seems possible that masks and social distancing cut down on colds and allergies, it is also possible that the kids were just wiping their noses with the insides of the masks.
- My allergies have always been triggered by mowing and other yard work. Three weeks ago, I began wearing a mask and safety goggles while mowing. I suffered no allergy symptoms. I've done the mask and goggles every time since, and still no symptoms. Scientific? Nope. Good enough to keep me wearing a mask for mowing? Yep.
Since I have masks lying around I too am suiting up for yard work. Helps a lot.