No "Shaky" Short Term but Inadvisable Long Term
We can eschew shaking hands for the sake of covid-19 mitigation short term but, as a biologist, I think we have evolved to inoculate ourselves with low doses of pathogens obtained through close human contact. This is essential to our survival AS A SPECIES. If you take a human and, at birth, put him in a bubble and give him sterilized food, that person will die within days if not hours when exposed to a normal environment. But, the thing is, this need to prime our immune systems is neverending (that's why Bill Gates hopes to remain top capitalist by one day supplying the world with vaccines). Other animals get their "immunizations" through the ingestion of feces, licking of paws, or through their food which they do not wash before consuming. Even in birth, many animals get their first dose of motherly probiotics when they "first see the light." Shaking unwashed hands is natures way of vacinating. You may object that "I can do my own vaccinating, thank you....