Vitamin D Deficiency May increases COVID-19 Risk

People who are deficient in vitamin D may be at higher risk of contracting the novel coronavirus than those with sufficient levels, according to the results of a new retrospective study from Illinois.

Individuals with untreated vitamin D deficiency were nearly twice as likely to test positive for COVID-19 relative to their peers with adequate vitamin D levels.

“These findings appear to support a role of vitamin D status in COVID-19 risk,” the authors say in the study, published online September 3 in JAMA Network Open.

“Vitamin D is important to the function of the immune system and vitamin D supplements have previously been shown to lower the risk of viral respiratory tract infections. Our statistical analysis suggests this may be true for the COVID-19 infection,” lead author David Meltzer, MD, Ph.D., chief of hospital medicine at University of Chicago Medicine, Illinois, said in a news release from his institution.

Over 100 Scientists, Doctors, & Leading Authorities Call For Increased Vitamin D Use To Combat COVID-19

Scientific evidence indicates vitamin D reduces infections & deaths Dec 7, 2020

To all governments, public health officials, doctors, and healthcare workers,

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.

Vitamin D modulates thousands of genes and many aspects of immune function, both innate and adaptive. The scientific evidence1 shows that:

  • Higher vitamin D blood levels are associated with lower rates of SARS-CoV-2 infection.
  • Higher D levels are associated with a lower risk of a severe case (hospitalization, ICU, or death).
  • Intervention studies (including RCTs) indicate that vitamin D can be a very effective treatment.
  • Many papers reveal several biological mechanisms by which vitamin D influences COVID-19.
  • Causal inference modeling, Hill’s criteria, the intervention studies & the biological mechanisms indicate that vitamin D’s influence on COVID-19 is very likely causal, not just correlation.


Vitamin D is well known to be essential, but most people do not get enough. Two common definitions of inadequacy are deficiency < 20ng/ml (50nmol/L), the target of most governmental organizations, and insufficiency < 30ng/ml (75nmol/L), the target of several medical societies & experts.2 Too many people have levels below these targets. Rates of vitamin D deficiency <20ng/ml exceed 33% of the population in most of the world, and most estimates of insufficiency <30ng/ml are well over 50% (but much higher in many countries).3 Rates are even higher in winter, and several groups have notably worse deficiency: the overweight, those with dark skin (especially far from the equator), and care home residents. These same groups face increased COVID-19 risk.

It has been shown that 3875 IU (97mcg) daily is required for 97.5% of people to reach 20ng/ml, and 6200 IU (155mcg) for 30ng/ml,4 intakes far above all national guidelines. Unfortunately, the report that set the US RDA included an admitted statistical error in which the required intake was calculated to be ~10x too low.4 Numerous calls in the academic literature to raise official recommended intakes had not yet resulted in increases by the time SARS-CoV-2 arrived. Now, many papers indicate that vitamin D affects COVID-19 more strongly than most other health conditions, with increased risk at levels < 30ng/ml (75nmol/L) and severely greater risk < 20ng/ml (50nmol/L).1

Evidence to date suggests the possibility that the COVID-19 pandemic sustains itself in large part through infection of those with low vitamin D, and that deaths are concentrated largely in those with deficiency. The mere possibility that this is so should compel the urgent gathering of more vitamin D data. Even without more datathe preponderance of evidence indicates that increased vitamin D would help reduce infections, hospitalizations, ICU admissions, & deaths.

Decades of safety data show that vitamin D has very low risk: Toxicity would be extremely rare with the recommendations here. The risk of insufficient levels far outweighs any risk from levels that seem to provide most of the protection against COVID-19, and this is notably different from drugs & vaccines. Vitamin D is much safer than steroids, such as dexamethasone, the most widely accepted treatment to have also demonstrated a large COVID-19 benefit. Vitamin D’s safety is more like that of face masks. There is no need to wait for further clinical trials to increase the use of something so safe, especially when remedying high rates of deficiency/insufficiency should already be a priority.

Therefore, we call on all governments, doctors, and healthcare workers worldwide to immediately recommend and implement efforts appropriate to their adult populations to increase vitamin D, at least until the end of the pandemic. Specifically to:

  1. Recommend amounts from all sources sufficient to achieve 25(OH)D serum levels over 30ng/ml (75nmol/L), a widely endorsed minimum with evidence of reduced COVID-19 risk.
  2. Recommend to adults vitamin D intake of 4000 IU (100mcg) daily (or at least 2000 IU) in the absence of testing. 4000 IU is widely regarded as safe.5
  3. Recommend that adults at increased risk of deficiency due to excess weight, dark skin, or living in care homes may need higher intakes (eg, 2x). Testing can help to avoid levels too low or high.
  4. Recommend that adults not already receiving the above amounts get 10,000 IU (250mcg) daily for 2-3 weeks (or until achieving 30ng/ml if testing), followed by the daily amount above. This practice is widely regarded as safe. The body can synthesize more than this from sunlight under the right conditions (e.g., a summer day at the beach). Also, the NAM (US) and EFSA (Europe) both label this a “No Observed Adverse Effect Level” even as a daily maintenance intake.
  5. Measure 25(OH)D levels of all hospitalized COVID-19 patients & treat w/ calcifediol or D3, to at least remedy insufficiency <30ng/ml (75nmol/L), possibly with a protocol along the lines of Castillo et al ‘20 or Rastogi et al ’20, until evidence supports a better protocol.

Many factors are known to predispose individuals to higher risk from exposure to SARS-CoV-2, such as age, being male, comorbidities, etc., but inadequate vitamin D is by far the most easily and quickly modifiable risk factor with abundant evidence to support a large effect. Vitamin D is inexpensive and has negligible risk compared to the considerable risk of COVID-19.

Important for Immune Function

Meltzer and colleagues studied 489 University of Chicago Medicine patients (mean age 49 years, 75% women) whose vitamin D levels were determined in the 2 months before being tested for COVID-19.

Vitamin D deficiency was defined as < 20 ng/mL 25-hydroxycholecalciferol or < 18 pg/mL 1,25-dihydroxycholecalciferol.

Vitamin D status was categorized as likely deficient for 124 participants (25%), likely sufficient for 287 (59%), and uncertain for 78 (16%).

A total of 71 participants (15%) tested positive for COVID-19.

In a multivariate analysis, a positive COVID-19 test was significantly more likely in those with likely vitamin D deficiency than in those with likely sufficient vitamin D levels at the time of COVID-19 testing (relative risk [RR], 1.77; 95% CI, 1.12 – 2.81; = .02).

The estimated mean rate of COVID-19 in the deficient group was 21.6% compared with 12.2% in the sufficient group.

Testing positive for COVID-19 was also associated with increasing age up to age 50 years (RR, 1.06; P = .02) and race other than White (RR, 2.54; P = .009)
Protective Effect of Treatment?

The findings also raise the possibility that treatment for vitamin D deficiency may lower the risk of COVID-19, the researchers say.

Patients with deficient vitamin D levels who had their vitamin D treatment increased did not appear to have increased risk for COVID-19.

This suggests a “protective effect of treatment, but the confidence intervals on estimated rates for these groups are too wide to exclude the possibility of no treatment effect,” Meltzer and colleagues note.”If vitamin D does reduce COVID-19 incidence, it is tempting to consider whether it might reduce COVID-19 transmission,” they hypothesize.

Because vitamin D strengthens innate immunity it could be expected to decrease COVID-19 infection and transmission. Vitamin D also affects zinc metabolism, which decreases the replication of coronaviruses.

As previously reported by Medscape Medical News, a recent study from Israel suggested low plasma vitamin D levels are an independent risk factor for COVID-19 infection and hospitalization.

In that study, participants positive for COVID-19 were 50% more likely to have low vs normal vitamin D levels in a multivariate analysis that controlled for other confounders.

Half of Americans are deficient in Vitamin D, with much higher rates seen in African Americans, Hispanics, and individuals living in areas like Chicago where it is difficult to get enough sun exposure in winter.

“Understanding whether treating Vitamin D deficiency changes COVID-19 risk could be of great importance locally, nationally, and globally,” Meltzer said. “Vitamin D is inexpensive, generally very safe to take, and can be widely scaled.”

Meltzer and colleagues say randomized clinical trials are now needed to see whether broad population interventions and interventions among groups at increased risk of vitamin D deficiency and COVID-19 could reduce COVID-19 cases.

Effect Of CBD On COVID-19 Suffering | The Study Situation

Marvin Klemp, You can also see CBD oil and How it can reduce COVID19 Complications

Can CBD prove to be a life-saving ally in the fight against COVID-19? Let’s look at what science has to say about the role of cannabinoids and cannabidiol (CBD), an active component of the cannabis plant. Could these components be effective and eventually lead to therapies?

you can read the full article at


About Post Author