I live with elderly parents. Or maybe they live with me. I'm not sure how that should be phrased. What can't be denied is that my father (whose birthday is today: Happy Birthday, Dad!) is medically vulnerable at this point in his life. So for handling flu season, I turn to a strange blend of science and magic.
Modern science provides this entire household with flu shots as soon as they are available. A single flu at this stage could take Dad out. I refuse to be the one who brings into the house. All four adults in the household get those shots every year.
We do our best to keep the house reasonably humid which sounds funny in Florida, but this winter has been unusually dry with repeated cold air invasions from the north. Dry air allows viral particles to remain airborne longer. In higher humidity, they get weighed down and pulled to the floor or other surfaces. In dry air, we breathe the little bastages and all hell breaks loose. So in really dry weather, we'll do our best to bring up humidity in the house a little. And we step up the house-keeping routine so our food prep surfaces and the surfaces we all touch are cleaned often.
From there, I spend the entirety of the winter taking a nightly hit from a bottle of Sambucol. 10ml to prevent viral infection, and up to 40 ml per day to treat in acute situations. For years, science went back and forth about whether or not this stuff worked. First is was no. Then yes. Then pff, of course not, it's wishful thinking. Then a series of articles published the mechanism by which black elderberry worked: By blocking viral insertion into cells so the viruses can't replicate. Y'all, this stuff is basically contraception for viruses. That's some serious magic.
Articles on the effectiveness of Black Elderberry: