My tip is not to get it in the first place. When I was in the Air Force we were required to get flu shots regularly. I swear, sometimes it was more than twice a year. Everytime I got a flu shot, I got the flu that same week. And it wasn’t eased up by the shot either, oh no. It was just like having the flu. And sometimes it was like the Martian death flu. Would last a week. Awful!
After I retired, I just refused to get the shots. I was a lot better feeling. Still got sick, but nowhere near as bad. Just barely worse than a cold really.
And then I discovered Vitamin D3. Note, not vitamin D. D3. D3 is what you need. It’s not really a vitamin, it’s a hormone. It’s a hormone that virtually everyone is deficient in. Few foods contain it. So getting it in our diets near impossible. So it must be supplemented. Or, you could get it in the sun. If you were to lay nude in the mid day sun, (from 11 to 1, before or after these times the sunlight must travel through too much atmosphere, and the effect is negated). After 30 minutes (which by then you have dramatic diminishing returns, so no reason to lay out longer) after 30 minutes your body can produce around equal to 30,000 IU’s of vitamin D3.
Of course, I’m not ever going to be able to make that happen, so I supplement. I take 5,000 IU twice a day. I started out with 40,000 a day. And after a few months I began to feel ill, so I backed off a bit. It’s fat soluable, so it builds up. Since 2007, I haven’t had the flu, not once. And that’s with little kids hanging around. Bringing back preschool germs, snotty noses, croup, you know the routine. Kids bring it home, everyone else gets it. Everyone but me. After a few years of me bragging about it the wife noticed it. She’s rarely ever sick now as well.
I looked into the ‘how it was decided that 600 IUs were determined as recommended daily’ and I was aghast. Completely unscientific method. Since in the early 20th century, moms were giving kids 1 spoon full of cod liver oil, or was it caster oil? Every day, just because, and we all did fine, that that amount must be an ok limit. Turns out that was 600 IUs. Nobody questioned it. So it became the standard. 
This hormone is extremely important to immunology. Being deficient in it makes it easy for infections to take hold. I have also been allergy free since then for the most part. In spring and fall during the worst of hay fever season in North Carolina, I barely get the sniffles, when previously I’d be sneezing pretty much non stop unless I was doped up on various antihistamines.
Go check Steve Gibson’s Health section on his grc.com website. Yes, it’s a tech site, but he does have a health section there where he excels at n=1.
