I wrote my protocol in this forum in, IIRC, May 2020. It was vitamin D3 and for those who were overweight or obese... dieting. My wife and I followed this protocol throughout the pandemic. I kept my D-level over 50 and up to 80 during the Delta wave. The allopathic "normal" range is 20-30. However, studies have shown that blacks, elderly, and obese all have low to very low vitamin D levels. Not coincidentally, these are the groups hardest hit by covid. A doctor told me that the typical senior (65+) who came into his practice had D levels of 15-17.
A study published in the last few months found that vitamin D was both preventive and reduced the risk of death/hospitalization. I think the prevention level was 70-something percent. I don't remember the death/hospitalization reduction.
Before we had vaccines, vitamin D was NEVER recommended. Losing weight if you were obese was NEVER recommended. Fauci had a bully pulpit every freaking day back in 2020 annd 2021. Every single interview, he stressed masks, social distancing, and once the vaccines were available, getting vaccinated. NEVER did he add, "And if you're obese, for goodness sakes, lose weight!"