The records of 1,176 patients admitted between April 2020 and February 2021 to the Galilee Medical Center (GMC) with positive PCR tests were searched for vitamin D levels measured two weeks to two years prior to infection. Patients with vitamin D deficiency (less than 20 ng/mL) were 14 times more likely to have severe or critical case of COVID than those with more than 40 ng/mL. Strikingly, mortality among patients with sufficient vitamin D levels was 2.3%, in contrast to 25.6% in the vitamin D deficient group.
Bar-Ilan University. “Pre-infection deficiency of vitamin D is associated with increased disease severity and mortality among hospitalized COVID-19 patients: Study affirms that sufficient vitamin D levels may positively influence the outcome of infection.” ScienceDaily. http://www.sciencedaily.com/releases/2022/02/220203161135.htm (accessed February 6, 2022).
Links to a few older posts on the same topic.
Vitamin D Treatment and Covid-19 Related Outcomes – Hospital del Mar, Barcelona, Spain
Does Vitamin D Deficiency Raise COVID-19 Risk? – JAMA
More on Vitamin D and Covid-19 Vitamin D and Mortality Risk in People With CVD
lifeunderwriter.net 
More reason to continue my daily vitamin D supplement.
Vitamin D supplementation for me is just one of those things I take for granted. I just have to continually remind myself not everyone knows about the possible benefits so keep reading, keep posting.
I take calcifediol instead of D3 and I have a lot more energy now. When you get older, nutritional uptake is less effective. Extra fat and liver problems are more likely with age. And if you take calcifediol, you can drink alcohol without missing out on vitamin D.
Interesting insights. Thanks!