Several months ago I tried to give blood to get the free antibody test because I thought I'd had COVID-19 having had several of the symptoms though I tested negative. It turned out my Vitamin-D level was way too low (first time ever) and I had to get it up in order to get my test and eventually test negative again. When I went to my regular doctor he prescribed Vitamin-D which was only about $6. Hardly profitable to the drug companies. I'll read the articles and if I have any thoughts I'll pass them along.