The only known cold and ‘flu preventative (besides hygiene) is zinc.
Every year billions of pills are popped and better than 99% are nothing that can help. Sadly, antibiotics are prescribed to many for a viral infection, and the USA USDA still refuses to ban routine feeding of antibiotics to cattle (faster growth is a side effect, it seems) and so the human race is marching, indeed jogging, towards a time when antibiotics become completely useless. Drug resistance happens, even to those who deny Darwinian evolution, and the resulting ‘superbugs’ could well kill us all, eventually.
I don’t really fancy dying of TB, bacterial meningitis or any of the hundreds of “almost defeated” bacterial infections out there, thanks very much.
So, how about you spend a tiny amount on not needing to visit the doctor with a sore throat and runny nose? After all, a lot of sick folks who pop too many antibiotics hang out there, and in hospitals too!
Buy some zinc tablets. Take them (following and according to the instructions) I take mine with a glass of orange juice. It tastes nice, and although vitamin C in huge doses has been claimed to be a cold preventative, studies show little impact. But it won’t hurt you unless, like Dilbert, you are allergic to citrus.
The zinc, on the other hand, has been proven to fight colds and viral infections. And, just to stress the point, it is the only thing that has been.
(And if you believe in homeopathy, cupping, accupunture or whatever, then fine. They don’t work at all, let alone on a virus far smaller than a pinhead.)
Anyway, this isn’t medical advice, etc. And I’m not a doctor. Oh, and don’t feed drugs to cows unless they need it!