For close to fifteen years I have had very good luck fighting viruses with Vitamin C, Vitamin D and Zinc. As soon as I feel symptoms of a cold or flu starting I take those three vitamins four times a day until symptoms disappear. Often I'm symptom free the next day onward. My son is a doctor in his second year of residency. He has treated a lot of Covid patients. For those less severe cases that don't require hospitalization he prescribes C, D and zinc with good outcomes. These supplements in high dose turbocharge your immune system.
Caution: Zinc should not be taken long term (more than 5-6 days) because it ties up your bodies receptors preventing uptake of other essential minerals.