Public Health England
Vitamin D recommendations
https://www.gov.uk/government/news/ph...

Vit D and COVID

https://www.ncbi.nlm.nih.gov/pubmed/3...
Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths.

Prevalence and correlates of vitamin D deficiency in US adults
https://www.ncbi.nlm.nih.gov/pubmed/2...
https://www.healthline.com/nutrition/...

https://www.healthline.com/nutrition/...

About 42% of the US population is vitamin D deficient. However, this rate rises to 82% in black people and 70% in Hispanics

Vit D deficiency in Ireland
https://tilda.tcd.ie/publications/rep...
Vitamin D is essential for bone and muscle health


Arizona University
https://integrativemedicine.arizona.e...
https://www.researchsquare.com/articl...

https://www.ncbi.nlm.nih.gov/pmc/arti...

https://www.ncbi.nlm.nih.gov/pmc/arti...