Could Many COVID-19 Deaths Have Been Prevented?

Mounting research on vitamin D's effects on COVID-19 has more clinicians and researchers calling for its wider use

In recent weeks and months, there have been more studies(1) demonstrating the benefits of vitamin D against COVID-19. More than 200 doctors, scientists, and leading authorities have signed an open letter(2) calling for increased use of vitamin D in the fight against COVID-19.

“Research shows low vitamin D levels almost certainly promote COVID-19 infections, hospitalizations, and deaths. Given its safety, we call for immediate widespread increased vitamin D intakes,” the letter states.

“Vitamin D modulates thousands of genes and many aspects of immune function, both innate and adaptive,” it continues before listing some of the validated findings on vitamin D.

The authors note that higher vitamin D blood levels are associated with lower rates of SARS-CoV-2 infection and a lower risk of a severe case (hospitalization, ICU, or death).

Vitamin D’s effectiveness is also shown in intervention studies, they say, adding that many research papers reveal several biological mechanisms by which vitamin D influences COVID-19.

The letter recommends taking enough vitamin D to achieve a blood level of at least 30 ng/mL (75 nmol/L). The authors urge testing all hospitalized COVID-19 patients and adding vitamin D to the treatment protocol for any patient whose level is below 30 ng/mL. Many other doctors are also urging government health agencies to get onboard with vitamin D recommendations.

Two experts in the Netherlands shared similar thoughts with the NL Times in December:(4)

“There is a growing consensus in the scientific world about the important role of vitamin D,” Manfred Eggersdorfer, professor of healthy aging at the University Medical Center Groningen, told the Times, adding that vitamin D can reduce the chances of catching a coronavirus and shorten the duration of infection.

Professor of immunology at Wageningen University, Huub Savelkoul, told the Times the wait-and-see attitude governments have adopted is frustrating to the scientific community.

“There are more and more studies showing the benefit of vitamin D. I think it is a kind of arrogance that the government wants to wait for a meta-study first. It seems as if we don’t care that people come to the hospital and die in the meantime. You have to be careful with that comment, but that’s where my frustration lies,” he said.

Vitamin D Optimization Is Powerful Prevention

In a December 23, 2020, Fox News interview(5,6), Dr. Peter Osborne with the Origins Nutrition Center stated that the most recent studies suggest 9 out of 10 COVID-19 deaths could have been prevented had people had adequate vitamin D levels.

While I suspect this might be an overestimation, there’s no doubt in my mind that optimizing vitamin D levels among the general population would significantly lower COVID-19 incidence and death.

Osborne shared an example showing this understanding is growing among clinicians.

“At the East Virginia School of Medicine there’s a COVID protocol that includes vitamin D,” Osborne said. “So, if you’re hospitalized for COVID, they’re automatically putting you on between 20,000 and 60,000 units of vitamin D. This is part of their standard of care protocol in that hospital system.”

Osborne also recommends using vitamin C and zinc, as well as quercetin, which allows for greater zinc absorption. Quercetin also boosts type 1 interferon, which signals infected cells to produce proteins that stop the virus from replicating. Type 1 interferon works synergistically with vitamin C.

As noted in a December 2020 Frontiers in Nutrition review:(7)”During the COVID-19 pandemic, the adequate intake of zinc and vitamins C and D may represent a promising pharmacological tool due to the high demand for these nutrients in the case of contact with the virus and onset of the inflammatory process.”

However, vitamin D is not my first choice for acute illness that requires immediate treatment. While high-dose vitamin D loading may be helpful in some respects, my first choice for treating acute respiratory illness is nebulized hydrogen peroxide, which I’ll discuss at the end of this article. It goes to work immediately, while vitamin D requires time, at bare minimum, days, to make a difference.

With respect to preventing COVID-19 deaths, I strongly believe that nebulized hydrogen peroxide could easily prevent at least 90 percent of the deaths if administered properly. It deeply saddens me to see so many die needlessly because they don’t use this incredibly inexpensive and safe therapy.

Vitamin D Improves COVID-19 Outcomes

Now, bear in mind that prevention and treatment are not the same. I firmly believe that vitamin D optimization will help prevent COVID-19 infection and reduce your risk of severe symptoms should you contract it.

In fact, I launched an information campaign about vitamin D back in June 2020, which included the release of a downloadable scientific report that detailed the science behind vitamin D. This report, as well as a two-minute COVID-19 risk quiz is available on

There’s also evidence to show high-dose vitamin D loading can improve COVID-19 outcomes even in acute and severe cases. According to a December 2020 randomized, double-blind study(8) in the European Journal of Integrative Medicine, giving critically ill COVID-19 patients high doses of vitamin D significantly reduced the number of days they had to spend in the ICU. They were also less likely to need ventilation.

According to the authors:(9)”Thirty patients completed the study. The results show that injection of vitamin D leads to a significant increase in the mean changes of vitamin D level on the seventh day of the study and TAC [total antioxidant capacity] levels.

“ICU length of stay was 18.3±8.4 and 25.4±6.6 days in the intervention and placebo arms of the study. Twelve patients in the placebo group and 5 in the vitamin D group died within the 28-day study period. The duration of mechanical ventilation was 15.7± 9.3 vs. 22.6± 9.1 days in vitamin D and placebo arms, respectively.”

Similarly, a mathematical reanalysis conducted by MIT researchers(10) of a calcifediol trial concluded there’s a “strong role for vitamin D in reducing ICU admissions of hospitalized COVID-19 patients.” The analysis looked at data from an earlier trial(11) done on hospitalized COVID-19 patients in Córdoba, Spain.

As explained by the authors of the analysis:(12)”… the treatment was associated with reduced ICU admissions with very large effect size and high statistical significance, but the study has had limited impact because it had only 76 patients and imperfect blinding, and did not measure vitamin D levels pre- and post-treatment or adjust for several comorbidities.”

In an effort to account for these shortcomings, they reanalyzed the data using statistical techniques, concluding that “the randomization, large effect size, and high statistical significance address many of these concerns.”

For starters, they found that “random assignment of patients to treatment and control groups is highly unlikely to distribute comorbidities or other prognostic indicators sufficiently unevenly to account for the large effect size.”

They also demonstrated that the imperfect blinding didn’t have a negative impact, as it would have had to have “an implausibly large effect to account for the reported results.”

To double-check their findings, they also compared the data with two other randomized clinical trials of vitamin D supplementation for COVID-19, one from India and another from Brazil. In conclusion, the authors stated that “the Córdoba study provides sufficient evidence to warrant immediate, well-designed pivotal clinical trials of early calcifediol administration in a broader cohort of inpatients and outpatients with COVID-19.”

Irish Experts Call for Increased Recognition of Vitamin D

In addition to the open letter mentioned earlier, the Irish Covit-D Consortium is also calling for greater use of vitamin D against COVID-19, citing evidence showing it can lower the risk of death from COVID-19 in the elderly by as much as 700 percent.(13)

In a position statement(14) published in the Irish Journal of Medical Science, the team urges health professionals and policy-makers “to recognize the importance of enhanced vitamin D in … the optimization of immune response” and to “develop explicit population guidance and clinical protocols for vitamin D supplementation at … effective doses.”

“The accumulation of evidence linking low vitamin D levels and COVID-19 is now considerable,” Dr. Dan McCartney, program director of human nutrition and dietetics at TU Dublin and Trinity College Dublin, told Ireland’s Herald.

“This evidence includes studies which show an increased risk of infection in those with low vitamin D levels and a 25 to 30-fold reduced risk of ICU admission and a substantial reduction risk of death in older COVID-19 patients supplemented with vitamin D,” he said.

Vitamin D Speeds Viral Clearance

Another recent study,(16) published in November 2020 in the Postgraduate Medical Journal, looked at oral vitamin D supplementation on SARS-CoV-2 viral clearance. This study included only asymptomatic or mildly symptomatic SARS-CoV-2-positive individuals who also had vitamin D deficiency (a vitamin D blood level below 20 ng/mL).

Participants were randomly assigned to receive either 60,000 IUs of oral cholecalciferol (nano-liquid droplets) or a placebo for seven days. The target blood level was 50 ng/mL. Anyone who hadn’t achieved a blood level of 50 ng/mL after the first seven days continued to receive the supplement until they reached the target level.

Periodically, all participants were tested for SARS-CoV-2 as well as fibrinogen, D-dimer, procalcitonin and CRP, all of which are inflammatory markers. The primary outcome measure of the study was the proportion of patients testing negative for COVID-19 before day 21 of the study, as well as changes in inflammatory markers.

“A greater proportion of vitamin D-deficient individuals with SARS-CoV-2 infection turned SARS-CoV-2 RNA negative with a significant decrease in fibrinogen on high-dose cholecalciferol supplementation,” reported the study authors.

Vitamin D Slows COVID-19 Spread

As reported by KRGV 5 News in Texas, doctors in the Rio Grande Valley are also urging people to check their vitamin D levels and supplement if they’re deficient.

That move was inspired by research(18,19) like that published in the Journal of Endocrinology and Metabolism which suggests people who have low vitamin D levels are more prone to contracting SARS-CoV-2 infection and more likely to spread the infection to others.

“Vitamin D deficiency was found in 82.2 percent of COVID-19 cases and 47.2 percent of population-based controls … Vitamin D-deficient COVID-19 patients had … a longer length of hospital stay than those with serum 25OHD levels ≥20 ng/mL,” noted the paper.

“According to our results, vitamin D treatment should be recommended in COVID-19 patients with serum 25OHD deficiency, since this approach might have beneficial effects in both the musculoskeletal and the immune system,” wrote the authors.

How Vitamin D Impacts COVID-19

On Oct. 31, 2020, my own vitamin D review,(20) co-written with William Grant and Dr. Carol Wagner, both of whom are part of the GrassrootsHealth expert vitamin D panel, was published in the peer-reviewed journal Nutrients. You can read the paper for free on the journal’s website.

As noted in that paper, dark skin color, increased age, pre-existing chronic conditions, and vitamin D deficiency are all features of severe COVID-19 disease, and of these, vitamin D deficiency is the only factor that is readily and easily modifiable.

You may be able to reverse chronic disease, but that typically takes time. Optimizing your vitamin D, on the other hand, can be achieved in just a few weeks, thereby significantly lowering your risk of severe COVID-19.

In our paper, we review several of the mechanisms by which vitamin D can reduce your risk of COVID-19 and other respiratory infections, including but not limited to the following:(21)

  • Reducing the survival and replication of viruses(22) and inflammatory cytokine production
  • Maintaining endothelial integrity—Endothelial dysfunction contributes to vascular inflammation and impaired blood clotting, two hallmarks of severe COVID-19
  • Increasing angiotensin-converting enzyme 2 (ACE2) concentrations, which prevents the virus from entering cells via the ACE2 receptor—ACE2 is downregulated by SARS-CoV-2 infection, and by increasing ACE2, you also avoid excessive accumulation of angiotensin II, a peptide hormone known to increase the severity of COVID-19

Vitamin D is also an important component of COVID-19 prevention and treatment because it boosts your overall immune function by modulating your innate and adaptive immune responses, it reduces respiratory distress(23), and it improves overall lung function.

Vitamin D also helps produce surfactants in your lungs that aid in fluid clearance(24) and lowers your risk of comorbidities associated with poor COVID-19 prognosis, including obesity,(25) Type 2 diabetes,(26) high blood pressure,(27) and heart disease(28).

Data from 14 observational studies—summarized in Table 1 of our paper(29)—suggest that vitamin D blood levels are inversely correlated with the incidence and severity of COVID-19, and the evidence currently available generally satisfies Hill’s criteria for causality in a biological system.(30)

COVID-19 Features Related to Vitamin D Status

Our paper(31) also details several features of COVID-19 that suggest vitamin D deficiency is at play in this illness. For starters, SARS-CoV-2 emerged in the winter in the northern hemisphere, and as we moved into summer, positive tests, hospitalizations and death rates fell. So, generally, COVID-19 prevalence has been inversely correlated with solar UVB doses and vitamin D production, just like seasonal influenza.

Secondly, people with darker skin have higher COVID-19 case and death rates than Caucasians. Vitamin D is produced in your skin in response to sun exposure, but the darker your skin, the more sun exposure you need in order to maintain an optimal vitamin D level. As a result, vitamin D deficiency tends to be far higher among blacks and dark-skinned Hispanics. Blacks and Hispanics are also high-risk groups for COVID-19.

Thirdly, one of the lethal hallmarks of COVID-19 is the cytokine storm that can develop in severe cases, which manifests as hyperinflammation and tissue damage. Vitamin D is known to regulate inflammatory cytokine production, thereby lowering this risk. Lastly, vitamin D is an important regulator of your immune system, and dysregulation of the immune system is a hallmark of severe COVID-19.

A growing body of evidence shows that vitamin D plays a crucial role in disease prevention and maintaining optimal health. There are about 30,000 genes in your body, and vitamin D affects nearly 3,000 of them, as well as vitamin D receptors located throughout your body.

For a more detailed and comprehensive analysis of the connection of vitamin D and COVID-19, please review the report on that I created that could be used to address any health care professionals who would disagree with this recommendation.

Also included is a shortened version of the document that will be better to educate those that you would like to convince of the importance of getting your vitamin D levels optimized. Doing so has other benefits, including slashing your risk for cancer and helping prevent at least 16 different types of cancer, including pancreatic, lung, ovarian, prostate and skin cancers.

Vitamin D from sun exposure also radically decreases your risk of autoimmune diseases such as multiple sclerosis (MS) and Type 1 diabetes.

Magnesium Is Necessary to Activate Vitamin D

Since more than half the population doesn’t get enough magnesium and far more are likely deficient, magnesium supplementation is recommended when taking vitamin D supplements. This is because magnesium helps to activate vitamin D, as the enzymes that metabolize vitamin D in your liver and kidneys require magnesium.

What GrassrootsHealth observed in testing and analyzing nutrient intakes from more than 15,000 patients is that about half of those taking vitamin D supplements were unable to normalize their vitamin D levels until they started to take supplemental magnesium.

They also found that those who don’t take supplemental magnesium need, on average, 146 percent more vitamin D per day to achieve a healthy blood level of 40 ng/ml (100 nmol/L), compared to those who take at least 400 mg of magnesium along with their vitamin D supplement.

The only real way to know if you are deficient in these nutrients is to get tested.

How Much Vitamin D Should You Take

If you know your vitamin D level you can use the calculator below to find the best dose to take.

If you are unable or unwilling to get a vitamin D test, they have found that the average dose to achieve a healthy vitamin D level of 40 ng/ml is about 8,000 units per day. If you are underweight you will want to reduce this dose to 6,000–7,000 units per day as heavier people tend to need more vitamin D.

Most of the 200 doctors, scientists, and authorities who signed the open letter mentioned at the beginning of this article recommend 4,000 IU a day.

How to Test Your Levels

If you would like to know your vitamin D or other nutrient levels, you can order a test kit from GrassrootsHealth Nutrient Research Institute. GrassrootsHealth has expanded its research projects to include a range of different tests, seeing how deficiency may be needlessly affecting the health of so many. Like its Vitamin D*action Project, the Magnesium*PLUS Focus Project will allow us all to take action on known science with a consensus of experts.

The Vitamin D*action Project has truly demonstrated the value measurement can have on public health. You can order a base test kit to get your vitamin D levels for $79. Besides learning your own levels, once the study of a community is completed, all the information from participants can be used to push for public health recommendations that will benefit everyone.

Nebulized Peroxide—My Favorite Treatment Choice

As mentioned earlier, while vitamin D is certainly important, if you develop symptoms of COVID-19, or any other respiratory infection for that matter, downing vitamin D will take time to take effect and may be too little, too late. I believe your best option at this point is to use nebulized peroxide. This is a home remedy I recommend everyone familiarize themselves with, as in many cases it can improve symptoms in mere hours.

Nebulizing hydrogen peroxide into your sinuses, throat, and lungs is a simple, straightforward way to augment your body’s natural expression of hydrogen peroxide to combat infections and can be used both prophylactically after known exposure to COVID-19 and as a treatment for mild, moderate, and even severe illness.

Dr. David Brownstein, who has successfully treated more than 100 COVID-19 patients with nebulized peroxide, published a case paper(32) about this treatment in the July 2020 issue of Science, Public Health Policy and The Law. He also reviews its benefits in our article “How Nebulized Peroxide Helps Against Respiratory Infections,” on

Nebulized hydrogen peroxide is extremely safe, and all you need is a desktop nebulizer and food-grade hydrogen peroxide, which you’ll need to dilute with saline to 0.1 percent strength. I recommend buying these items beforehand so that you have everything you need and can begin treatment at home at the first signs of a respiratory infection. In the video above, I go over the basics of this treatment in a video on

Dr. Joseph Mercola is the founder of An osteopathic physician, best-selling author, and recipient of multiple awards in the field of natural health, his primary vision is to change the modern health paradigm by providing people with a valuable resource to help them take control of their health. This article was originally published on

(1Vitamin D for COVID Listing of Studies
(2,) ( December 7, 2020
(4NL Times December 26, 2020
(5Fox News December 23, 2020
(6Fox 35 Orlando December 25, 2020
(7Frontiers in Nutrition December 7, 2020
(8,) (9European Journal of Integrative Medicine December 26, 2020: 101271
(10,) (12medRxiv December 21, 2020
(11The Journal of Steroid Biochemistry and Molecular Biology October 2020; 203; 105751
(13,) (15Herald December 30, 2020
(14Irish Journal of Medical Science November 21, 2020
(16Postgraduate Medical Journal November 12, 2020 DOI: 10.1136/postgradmedj-2020-139065
(17Postgraduate Medical Journal November 12, 2020 DOI: 10.1136/postgradmedj-2020-139065, Results
(18JCEM October 27, 2020; dgaa733
(19Endocrine Society October 27, 2020
(20,) (21,) (31Nutrients October 31, 2020;12, 3361; doi:10.3390/nu12113361
(22Nutrients, 2020;12:988
(23Advances in Pharmacological Sciences 2018; 2018: 8494816
(24ATS Journals October 5, 2010; 183(10)
(25Medicina 2019 Sep; 55(9): 541
( January 15, 2019
(27The Lancet Diabetes & Endocrinology September 1, 2014; 2(9): 682-684
(28Current Treatment Options in Cardiovascular Medicine 2012 Aug; 14(4): 414–424
(29Nutrients October 31, 2020;12, 3361; doi:10.3390/nu12113361, Table 1
(30Nutrients October 31, 2020;12, 3361; doi:10.3390/nu12113361, Table 3
(32Science, Public Health Policy and The Law July 2020; 1: 4-22 (PDF)

Dr. Joseph Mercola is the founder of An osteopathic physician, best-selling author, and recipient of multiple awards in the field of natural health, his primary vision is to change the modern health paradigm by providing people with a valuable resource to help them take control of their health.
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