Per the linked source, 41 studies including 2 randomized trials show that a vitamin D deficiency increases the severity of COVID-19 infections. Other sources (e

Per the linked source, 41 studies including 2 randomized trials show that a vitamin D deficiency increases the severity of COVID-19 infections. Other sources (example: https://www.bmj.com/content/371/bmj.m3872/rr-5 https://www.bmj.com/content/371/bmj.m3872/rr-5) also corroborate the scale of studies indicating a relationship between Vitamin D deficiency and COVID-19 health outcomes. Some notable findings: one randomized study of 50 people hospitalized for COVID-19 found that of everyone given a high dose of Vitamin D, only one ended up in the ICU (https://www.mayoclinic.org/diseases-conditions/coronavirus/expert-answers/coronavirus-and-vitamin-d/faq-20493088 https://www.mayoclinic.org/diseases-conditions/coronavirus/e...). And 80% of those hospitalized for COVID-19 have Vitamin D deficiency (https://www.webmd.com/lung/news/20200518/more-vitamin-d-lower-risk-of-severe-covid-19 https://www.webmd.com/lung/news/20200518/more-vitamin-d-lowe...). Seroconversion is also higher for those with Vitamin D deficiency (https://www.medrxiv.org/content/10.1101/2020.10.05.20206706v1.full.pdf https://www.medrxiv.org/content/10.1101/2020.10.05.20206706v...), meaning that you are also more likely to have caught COVID-19 at some point (in a way that you developed detectable antibodies) with VDD than without. Interestingly, overall Vitamin D deficiency in the US population is at around 42% (https://pubmed.ncbi.nlm.nih.gov/21310306/ https://pubmed.ncbi.nlm.nih.gov/21310306/), with some minorities having significantly higher prevalence. This might partially explain why the US has worse outcomes for COVID-19 than some other nations, and it may also explain the distribution of which demographic groups are more at risk for COVID-19. Lastly, the link between VDD and COVID-19 health outcomes also raises a different philosophical question: if those who face adverse health impacts from COVID-19 are at increased risk due to their own poor diet or lifestyle (as indicated by Vitamin D deficiency), should all of society have to shoulder the burden of mask mandates, lockdowns, and other impacts? Or should individuals be allowed to make decisions as to what activities they undertake and what risks they are OK with based on their own assessment of risks and benefits?