I've had Influenza A before in my mid-30s. To be honest, I couldn't even tell I had it. I had the sniffles, went to get a COVID check, and came back Influenza A-positive.

I did my usual, ran a few miles on the treadmill, did family walks all over, etc. I just felt lethargic - like I didn't sleep well at all, but I powered through it.

I know people who were absolutely bedridden with the flu. I can 100% believe some people can almost entirely brush it off too.