Good read, though I am surprised that the immune system was not mentioned in the article.

One of the big issues with Covid-19 is your autoimmune response. It is having a big response, known as a Cytokine Storm that can fill your lungs with fluids and kill.

Vitamin D has been known as a regulator of the immune system for some time.

This might be of extreme interest - it is to me, as I have an autoimmune condition.

"Historically, vitamin D has been associated with the regulation of bone metabolism. However, increasing evidence demonstrates a strong association between vitamin D signaling and many biological processes that regulate immune responses. The discovery of the vitamin D receptor in multiple immune cell lineages, such as monocytes, dendritic cells, and activated T cells credits vitamin D with a novel role in modulating immunological functions and its subsequent role in the development or prevention of autoimmune diseases."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6047889/

Diet is also of extreme interest to me. Eggs are a good, natural source of Vitamin D, though free range eggs have up to 42% more Vitamin D than caged hen eggs, and organic are even higher:

"Egg yolk from free range and organic systems contained a 42% greater concentration of vitamin D3 than did those from the indoor system (Table 1). In addition, organic egg yolks had a higher (P = 0.001) concentration of 25(OH) D3 than had egg yolks from free range and indoor systems, although no differences were observed between caged and free range systems."

"The current study indicates that the average effective vitamin D content of each egg is about 2 μg (excluding any effect of factors such as cooking), which would mean that one egg per day would contribute 20% of the UK RNI for vitamin D."

https://www.sciencedirect.com/science/article/pii/S0308814616319094