Vitamin D And The Risk Of Infection And Severity Of Symptoms Of COVID-19 Coronavirus

Adequate levels of vitamin D have been linked to reduced risk of respiratory infections and conditions including influenza, tuberculosis and even childhood asthma. But can vitamin D help fight off COVID-19 coronavirus? And if you do get infected, can adequate vitamin D levels reduce the severity of symptoms?

Billions of people are staying at home across the globe. Most are being told “stay indoors.” But is this a good idea?

We know that SARS-CoV-2 withers in the sunlight. UV light is being used to attack the virus in a variety of settings. But there may be another reason to stop hiding in your house and go outside: vitamin D.


Sunlight stimulates the skin to produce vitamin D. Vitamin D is essential for good immune health. And if several recent studies are correct (and everything points to that being true,) vitamin D may be essential to preventing COVID-19 infection. It may also be the key to limiting the severity of your symptoms if you do get infected.

Both of those sound like a really good reason to go catch some rays!

A new study, which has not been peer reviewed yet but seems to be scientifically sound, has concluded that your risk of having severe to critical symptoms of COVID-19 goes down when your vitamin D levels are healthy.


The study involved 212 COVID-19 patients in three different hospitals in southern Asia. This study is believed to be the first of it’s kind, in that it sought to directly link vitamin D levels to the severity of symptoms in COVID-19-infected patients.

We already know that vitamin D can reduce the risk of infection from the common cold, often caused by coronaviruses, but also by rhinoviruses and adenoviruses. (1) We also know that it bolsters cellular immunity (2,) modulates T cell activity in adaptive, or acquired immunity (3) and has a positive impact on the genes involved in antioxidation in cells and tissues (4.)

What the researcher in this case wanted to pinpoint was whether those with adequate vitamin D levels had less severe symptoms, on average, than those who did not. So the study broke symptom severity levels into four groups:


Mild – these people exhibited mild clinical symptoms and no pneumonia
Ordinary – these patients had respiratory symptoms, a fever and a confirmed diagnosis of pneumonia
Severe – these patients were in a state of hypoxia and had significant respiratory distress
Critical – these patients were experiencing respiratory failure and required critical (intensive) care

We know from hospital reports that virtually all ventilated patients are in the severe and critical symptom groups. Most are in the critical group.

Next, he spelled out 3 vitamin D level groups:
Deficient – serum vitamin D levels below 20 ng/ml
Insufficient – serum vitamin D levels between 21 and 29 ng/ml
Normal – serum vitamin D levels at or above 30 ng/ml


Once these parameters were spelled out, the researcher simply compared case symptom severity with average serum vitamin D levels across that symptom group. The findings were pretty clear.

Of the cases that were categorized as mild 98% of those patients had normal vitamin D levels. Here’s a different way to consider that. Of the 49 cases which were mild, only one patient had vitamin D levels that were either insufficient or deficient.

For purposes of comparison, let’s look at the other symptom groups. Of the patients with ordinary symptoms, only four of the 59 patients had normal vitamin D levels. In the severe (56 patients) and critical (48 patients) groups, only two patients in each group had normal vitamin D levels.


Here’s a great chart of the breakdown, courtesy of

The author wrote in his presentation letter: “for each standard deviation increase in serum (OH)D, the odds of having a mild clinical outcome rather than a severe outcome were approximately 7.94 times while interestingly, the odds of having a mild clinical outcome rather than a critical outcome were approximately more than 19.61 times.” (5)

In English, that means that having adequate vitamin D levels makes you about 8 times as likely to have a mild, rather than severe, case of COVID-19 if you get infected. Those same levels make you about 20 times more likely to be mild, rather than critical.

The newest research is telling us that COVID-19 survives in sunlight for about 2 minutes or less. Work is being done by bio-defense researchers at the Department of Homeland Security.


“Our most striking observation to date is the powerful effect solar light appears to have on killing the virus on both surfaces and in the air,” said Bill Bryan, the head of the science and technology directorate at the Department. (6)

Let’s review. We know UV light, particularly UVB light, has a pretty profound effect on COVID-19. We know that vitamin D has a positive effect on the immune system. We also have reason to believe normal vitamin D levels will give you a solid shot at avoiding COVID-19 symptoms beyond mild even if you do get infected. And last, we know that the body produces vitamin D in response to exposure to sunlight (even when filtered through light cloud cover, by the way.

So give yourself a leg up in fighting off the COVID-19 virus, or at least in fighting off the worst of symptoms if you do get it. Go outside and get some sun!

Keep the faith and keep after it!

Related Content –
How COVID-19 Coronavirus Beats The Immune System And Gets Into Lung Tissue
Support Your Body Like This To Fight COVID-19 Coronavirus
Hospitals Get Paid More For COVID-19 Coronavirus Patients: Fact Check

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  1. Rondanelli, M., Miccono, A., Lamburghini, S., Avanzato, I., Riva, A., Allegrini, P. & Perna, S., Self-care for common colds: the pivotal role of vitamin D, vitamin C, zinc, and Echinacea in three main immune interactive clusters (physical barriers, innate and adaptive immunity) involved during an episode of common colds—Practical advice on dosages and on the time to take these nutrients/botanicals in order to prevent or treat common colds. Evidence-Based Complementary and Alternative Medicine, 2018.
  2. Cantorna, M. T., Mechanisms underlying the effect of vitamin D on the immune system. Proceedings of the Nutrition Society,69, 2010
  3. Sharifi, A., Vahedi, H., Nedjat, S., Rafiei, H., & Hosseinzadeh‐Attar, M. J., Effect of single‐dose injection of vitamin D on immune cytokines in ulcerative colitis patients: a randomized placebo‐controlled trial. Apmis
  4. Lei, G. S., Zhang, C., Cheng, B. H., & Lee, C. H., Mechanisms of action of vitamin D as supplemental therapy for Pneumocystis pneumonia. Antimicrobial agents and chemotherapy, 2017

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