Hello Jeff C. ... responding to you from the 'other' side of Pennsylvania regarding your post. Finally had a chance to speak with my son Andrew who is a molecular biologist at a bio tech company in California and is presently working on a COVID-19 vaccine (like so many other places around the world), and I presented your post to him. Your information for the most part is accurate, and SARS-CoV2 infections will be less severe when contracted from someone who already has been infected because their immune system would be fighting the infection and establishing antibodies to do so. That is why medical professionals faced so many perils from this early on, because they were being exposed multiple times to a large number of individuals and had just turned symptomatic. Therefore, the severity of future infections really depends on who someone gets this from. A virus that spreads from a newly infected person will be just as potent as in the past, but infections from those in the latter stages of COVID-19 disease will likely be spreading a less potent version. New infections, as they are reported across North America, will consist of individuals with varying degrees of the illness. With that said, those people with vitamin D deficiencies are much more vulnerable to get a more serious infection. This is one of the reasons COVID-19 has hit the African-American communities so hard in terms of mortality, because this population base is typically deficient in vitamin D levels. He recommends having vitamin D levels checked by your PCP, and if deficient taking supplemental vitamin D to boost your numbers upward (beyond what you get from a multi-vitamin). And, by no means ever attempt to drink Clorox or Lysol as a supplement!