Vitamin D is being shown to mitigate the severity of Covid-19 infection
Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths William B. Grant, Henry Lahore, Sharon L. McDonnell, Carole A. Baggerly, Christine B. French, Jennifer L. Aliano, and Harjit P. Bhattoa Nutrients 2020, 12(4), 988 https://doi.org/10.3390/nu12040988
This recently published paper details the current research in support of higher vitamin D serum levels and decreased incidence of viral-induced respiratory diseases.
Through several mechanisms, vitamin D can reduce risk of infections.Those mechanisms include inducing cathelicidins and defensins that can lower viral replication rates and reducing concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs, leading to pneumonia, as well as increasing concentrations of anti-inflammatory cytokines.
First data to be published on COVID-19 severity and vitamin D levels: Vitamin D Supplementation Could Possibly Improve Clinical Outcomes of Patients Infected with Coronavirus-2019 (Covid-2019) https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3571484
In this preprint letter (not yet peer reviewed), data is presented from 212 COVID-19 patients who were hospitalised in three separate hospitals in Southern Asia comparing the severity of symptoms to vitamin D serum levels. Of the 212 cases, the average vitamin D level was 24 ng/ml (59 nmol/L)
49 (23%) cases were categorized as mild, with an average vitamin D level of 31 ng/ml (78 nmol/L)
59 (28%) were categorized as ordinary, with an average vitamin D level of 27 ng/ml (68 nmol/L)
56 (26%) were categorized as severe, with an average vitamin D level of 21 ng/ml (53 nmol/L)
48 (23%) were critical, with an average vitamin D level of 17 ng/ml (43 nmol/L)
86% of all cases among patients with normal vitamin D levels were mild, while 73% of cases among patients with vitamin D deficiency were severe or critical
For each standard deviation increase in vitamin D level, the odds of having a mild case compared to a severe case were 7.94 times more, and the odds of having a mild case compared to a critical case were 19.61 times more
All outcomes were statistically significant.
The odds of having a mild clinical outcome increase when serum (OH)D level increases. Alternatively, the odds of having a critical outcome increase when serum (OH)D level decreases. This means that serum(OH)D level in the body could account for the clinical outcomes of the patients infected with Covid-2019. An increase in serum (OH)D level in the body could either improve clinical outcomes or mitigate worst (severe to critical) outcomes. On the other hand, a decrease in serum (OH)D level in the body could worsen clinical outcomes of Covid-2019 patients.