Saliva is one natural secretion of. Living beings, that has anti-viral and antibiotic properties. 'Lick your wounds' is an age old saying that tells us this fact.
One of the main symptoms of Covid-19 is sore throat.
If one produces a quantity of saliva, which is very easy, and swallows it slowly, it would wash the throat area and most important, send it. Into highly acidic stomach, where the disease causing germs ir viruses get destroyed, irrevocably.
When this procedure. Is done a few times, in quick succession, primary infection. Is totally eliminated.
I don't actually know how to classify this suggestion, but you could use it, when a sore throat is.imminent, and you will never get it.
I am 82.5 years old, and Covid never touched me.