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Vitamin D Cuts SARS-CoV-2 Infection Rate by Half

Analysis by <https://www.mercola.com/forms/background.htm>Dr. Joseph Mercola


Story at-a-glance

    * Based on data from 191,779 American 
patients, people with a vitamin D level of at 
least 55 ng/mL (138 nmol/L) had a 47% lower 
SARS-CoV-2 positivity rate compared to those with 
a level below 20 ng/mL (50 nmol/L)
    * Based on data from 7,807 Israelis, those 
with a vitamin D level above 30 ng/mL (75 nmol/L) 
had a 58% to 59% lower risk of testing positive 
for SARS-CoV-2 compared to those with a vitamin D 
level below 29 ng/mL (74 nmol/L)
    * Having a vitamin D level below 30 ng/mL 
also approximately doubles your risk of being 
hospitalized with COVID-19, Israeli researchers found
    * Spanish researchers found giving 
hospitalized COVID-19 patients supplemental 
calcifediol (a vitamin D3 analog) in addition to 
standard of care lowered ICU admissions from 50% to 2% and eliminated deaths
    * An August 2020 study found patients who had 
a vitamin D level below 12 ng/mL (30 nmol/L) had 
a 6.12 times higher risk of severe disease 
requiring invasive mechanical ventilation, and a 
14.7 times higher risk of death compared to those 
with a vitamin D level above 12 ng/mL
Evidence showing vitamin D lowers your risk of 
SARS-CoV-2 infection, hospitalization, severe 
complications and death continues to mount. Most 
recently, a September 17, 2020, paper1 in PLOS 
ONE found people with lower vitamin D levels in 
their blood had a significantly higher risk of testing positive for SARS-CoV-2.


Higher Vitamin D Lowers Risk of Positive SARS-CoV-2 Test

The lead researcher in this study was Dr. Michael 
Hollick, who is widely recognized as one of the 
leading vitamin D experts in the world. I have 
interviewed him twice in the past. He and his 
team used retrospective observational analysis of 
SARS-CoV-2 tests to determine whether vitamin D 
blood levels impacted positivity rates.

Based on vitamin D results from the preceding 12 
months and SARS-CoV-2 test data from mid-March 
through mid-June 2020 from 191,779 patients from 
50 U.S. states, people with a vitamin D level of 
at least 55 ng/mL (138 nmol/L) had a 47% lower 
SARS-CoV-2 positivity rate compared to those with 
a level below 20 ng/mL (50 nmol/L).2 As noted by the authors:

“The SARS-CoV-2 positivity rate was 9.3% and the 
mean seasonally adjusted 25(OH)D was 31.7 
[ng/mL]. The SARS-CoV-2 positivity rate was 
higher in the 39,190 patients with ‘deficient’ 
25(OH)D values (<20 ng/mL) (12.5% …) than in the 
27,870 patients with ‘adequate’ values (30–34 
ng/mL) (8.1% …) and the 12,321 patients with values 55 ng/mL (5.9% …) …3

The risk of SARS-CoV-2 positivity continued to 
decline until the serum levels reached 55 ng/mL. 
This finding is not surprising, given the 
established inverse relationship between risk of 
respiratory viral pathogens, including influenza, and 25(OH)D levels.4

SARS-CoV-2 positivity is strongly and inversely 
associated with circulating 25(OH)D levels, a 
relationship that persists across latitudes, 
races/ethnicities, both sexes, and age ranges. 
Our findings provide impetus to explore the role 
of vitamin D supplementation in reducing the risk 
for SARS-CoV-2 infection and COVID-19 disease.”5

The graph below, obtained from GrassrootsHealth,6 
shows how the rate of positive SARS-CoV-2 results 
declines as vitamin D levels go up. Again, as you 
increase your vitamin D level from 20 ng/mL to 55 
ng/mL, your risk of having a positive SARS-CoV-2 test result decreases by 47%.

Even after adjustment for gender, age, ethnicity 
and latitude, the risk of having a positive test 
result was 43% lower among those with a vitamin D 
level of 55 ng/mL compared to those with a level 
of 20 ng/mL. I understand that the COVID-19 test 
may be worthless and counterproductive with its 
false positives, but it is the only metric we 
currently have to assess interventions.

positive SARS-CoV-2 results declines as vitamin D levels go up



Vitamin D Lowers Infection and Hospitalization Rates

That higher vitamin D levels lower the risk of 
SARS-CoV-2 infection (i.e., getting a positive 
test result) was also confirmed in an Israeli 
population-based study7,8 published in July 2020. 
This paper examined data from 7,807people tested 
for SARS-CoV-2 infection between February 1 and 
April 30 of 2020 who also had vitamin D test data available.

Here, those with a vitamin D level above 30 ng/mL 
(75 nmol/L) had a 59% lower risk of testing 
positive for SARS-CoV-2 compared to those with a 
vitamin D level between 20 ng/mL and 29 ng/mL (50 
to 74 nmol/L), and a 58% lower risk compared to 
those with a vitamin D level below 20 ng/mL (50 
nmol/L). The graph below, from a GrassrootsHealth 
report,9 illustrates the findings.

covid-19 infection risk by vitamin d level



Vitamin D Lowers Hospital and ICU Admissions

Seeing how higher vitamin D levels lowers your 
risk of testing positive for SARS-CoV-2 in the 
first place, it’s no surprise then that other 
data show higher vitamin D also lowers hospital and intensive care admissions.

The Israeli analysis10 above, for example, found 
that among individuals who tested positive for 
SARS-CoV-2 infection, those who had a vitamin D 
level below 30 ng/mL also had a 1.95 times (crude 
odds ratio) to 2.09 times (odds ratio after 
adjustment for demographics and psychiatric and 
somatic disorders) higher risk of being hospitalized for COVID-19.

In other words, having a vitamin D level below 30 
ng/mL about doubled the risk of being 
hospitalized with COVID-19. Vitamin D, when 
administered to hospitalized patients, can also 
lower their risk of needing intensive care.

This was demonstrated by Spanish researchers in a 
small randomized clinical study11,12,13,14 
published online August 29, 2020. They found 
hospitalized COVID-19 patients who were given 
supplemental calcifediol (a vitamin D3 analog 
also known as 25-hydroxycholecalciferol or 
25-hydroxyvitamin D) in addition to standard of 
care ­ which included the use of 
hydroxychloroquine and azithromycin ­ had 
significantly lower intensive care unit admissions.

Patients in the vitamin D arm received 532 
micrograms of calcifediol on the day of admission 
(equivalent to 106,400 IUs of vitamin D15) 
followed by 266 mcg on Days 3 and 7 (equivalent 
to 53,200 IUs16). After that, they received 266 
mcg once a week until discharge, ICU admission or death.

Of those receiving calcifediol, only 2% required 
ICU admission, compared to 50% of those who did 
not get calcifediol. None of those given vitamin 
D supplementation died, whereas 7.6% in the standard care group perished.
icu admission and death among hospitalized covid 19


Vitamin D Lowers COVID-19 Mortality

Other studies have also confirmed that higher 
vitamin D levels lowers your risk of 
complications and death from COVID-19. Among them 
is an August 2020 study17,18 published in the 
journal Nutrients, which found patients who had a 
vitamin D level below 12 ng/mL (30 nmol/L) had a 
6.12 times higher risk of severe disease 
requiring invasive mechanical ventilation, and a 
14.7 times higher risk of death compared to those 
with a vitamin D level above 12 ng/mL.

need for invasive mechanical ventilation


An Iranian study19,20 published online in 
mid-July 2020 also found that patients with 
vitamin D levels above 30 ng/mL (75 nmol/L) had 
better clinical outcomes and a far lower risk of 
death. Among COVID-19 patients over the age of 40 
who had vitamin D levels below 30 ng/mL, 20% 
died, compared to 9.7% of those with levels at or 
above 30 ng/mL. Among those with a vitamin D 
level of at least 40 ng/mL, only 6.3% died.


Low Vitamin D Is a Risk Factor for Respiratory Failure

Yet another study, published in the Journal of 
Endocrinological Investigation in August 2020, 
found vitamin D deficiency was a common factor 
among hospitalized patients in Italy who had been 
diagnosed with COVID-19 related respiratory failure.

These considerations support the recommendation 
that people at risk of influenza and/or COVID-19 
consider vitamin D supplementation to raise their 
25(OH)D concentrations above 40-60 ng/mL, and 
that treatment of patients infected with 
influenza and/or COVID-19 includes higher vitamin 
D doses. ~ Journal of Endocrinological Investigation August 2020

As reported by GrassrootsHealth:21

“Vitamin D levels were measured for each patient 
and were defined as insufficient (20-29 ng/ml or 
50-74 nmol/L), moderately deficient (10-19 ng/ml 
(25-49 nmol/L), and severely deficient (<10 ng/ml 
or <25 nmol/L). A normal vitamin D level was 
defined as 30 ng/ml (75 nmol/L) or higher.

81% of the patients with acute respiratory 
failure due to COVID-19 had vitamin D levels 
below 30 ng/ml (75 nmol/L); and 24% had severe 
vitamin D deficiency ( 10 ng/ml or 25 nmol/L).

When looking at mortality rates after 10 days of 
hospitalization, it was found that those with 
severe vitamin D deficiency had a 50% probability 
of death, compared to 5% among those with a 
vitamin D level greater than 10 ng/ml (25 nmol/L).

This is a 10 times higher risk of death among 
patients with severe vitamin D deficiency 
compared to patients with vitamin D levels >10 
ng/ml (>25 nmol/L) at 10 days of hospitalization."

survival rate among covid 19 patients


According to the study authors:

“Altogether, these considerations support the 
recommendation that people at risk of influenza 
and/or COVID-19 consider vitamin D 
supplementation to raise their 25(OH)D 
concentrations above 40-60 ng/mL, and that 
treatment of patients infected with influenza 
and/or COVID-19 includes higher vitamin D doses.”



How and Why Vitamin D Lowers COVID-19 Risks

In 
“<https://articles.mercola.com/sites/articles/archive/2020/09/14/bradykinin-hypothesis.aspx>Bradykinin 
Hypothesis Explains COVID-19 Complexities,” I 
reviewed how vitamin D lowers your risk of 
COVID-19 complications and death by inhibiting 
both cytokine22 and bradykinin storms.23 Vitamin D also:

Lowers viral replication24

Boosts your overall immune function by modulating 
both innate and adaptive immune responses

Reduces respiratory distress25

Improves overall lung function

Helps produce surfactants in your lungs that aid in fluid clearance26

Lowers your risk of comorbidities associated with 
poor COVID-19 prognosis, including obesity,27 
Type 2 diabetes,28 high blood pressure29 and heart disease30

All of these factors make it an important 
component of COVID-19 prevention and treatment. 
As temperatures and humidity levels drop ­ two 
factors that influence the viability of 
SARS-CoV-2 in air and on surfaces ­ it’s quite 
likely we’ll see a reemergence as we move into fall and winter.

My <https://www.stopcovidcold.com/>#StopCOVIDCold 
campaign seeks to raise awareness about the 
importance of vitamin D optimization to prevent a 
resurgence of COVID-19 hospitalizations and 
deaths. The two reports, which you can download 
free of charge on the #StopCOVIDCold website, 
provide in-depth information about the biological 
mechanics behind vitamin D’s protective effects.

Now, as the northern hemisphere heads into 
autumn, is the ideal time to check your vitamin D 
level and start taking action to raise it if 
you’re below 40 ng/mL (100 nmol/L). Experts 
recommend a vitamin D level between 40 and 60 
ng/ml (100 to 150 nmol/L). An easy and 
cost-effective way of measuring your vitamin D 
level is to order 
<https://daction.grassrootshealth.net/product/vitamin-d-home-test-kit/>GrassrootsHealth’s 
vitamin D testing kit.

Once you know your current vitamin D level, use 
the 
<https://www.grassrootshealth.net/project/dcalculator/>GrassrootsHealth 
vitamin D calculator31 to determine how much 
vitamin D you might need to reach your target level.

To optimize vitamin D absorption and utilization, 
be sure to take your vitamin D with vitamin K2 
and magnesium. As explained in 
“<https://articles.mercola.com/sites/articles/archive/2020/06/15/vitamin-d3-k2-and-magnesium.aspx>Magnesium 
and K2 Optimize Your Vitamin D Supplementation,” 
taking magnesium and vitamin K2 can lower your 
oral vitamin D requirement by as much as 244%.

Lastly, remember to retest in three to four 
months to make sure you’ve reached your target 
level. If you have, then you know you’re taking 
the correct dosage. If you’re still low (or have 
reached a level above 80 ng/mL), you’ll need to 
adjust your dosage accordingly and retest again 
in another three to four months.