Since I was at high risk due to age and certain physical conditions, and my dear wife was also at risk for age and different physical conditions, we got the COVID vaccine. Since then I have found several articles that suggest vitamin D is somehow a natural preventative for the effects of the virus. Exercise is also listed. Since I normally take a 3-mile walk every day except rainy days and days with too many appointments, I get my daily dose of nature sunshine-generated vitamin D. The one time I had a respiratory illness, the at-home COVID test kit was available. Whatever else I had, it wasn't COVID (after two negative tests a couple of days apart).
But then, Hippocrates (of the famous medical oath) was reported to say that "Walking is the best medicine for Man." OK, so my prescription is maybe about 2400 years old, but I still get it refilled frequently. And the comments about vitamin D and COVID are in no way facetious. I would consider that a contributing factor is that I have, for the last 15+ years, performed daily exercise to keep my body in as good a shape as I can manage, and that is also a factor in avoiding COVID.
I'm clearly NOT a homeopathic medicine person. But sometimes natural methods, though slow, are sound.