Over the past few months, several investigations have highlighted the apparent influence of vitamin D in COVID-19 incidence, severity and mortality. Interestingly, recent genetic analysis has produced a novel hypothesis1 that helps explain the unusual disease progression of COVID-19.
The hypothesis,2 published in the journal eLife in July 2020, specifically identifies bradykinin, a blood pressure regulating chemical controlled by your renin-angiotensin system (RAS), as a primary culprit.
As reviewed in greater depth in "Bradykinin Hypothesis Explains COVID-19 Complexities," the lethality of COVID-19 may be due to the virus' ability to induce a bradykinin storm. The effects of the virus on your RAS also adds further support to the recommendation to optimize your vitamin D.
In fact, the researchers who came up with the novel bradykinin hypothesis stress the usefulness of vitamin D, as it plays an important role in the RAS system3,4,5,6 and suppresses the biosynthesis of a compound called renin (REN), thereby preventing a deadly bradykinin storm.
Conversely, if you are vitamin D deficient, your renin expression is stimulated, and based on the latest data, that may render you more prone to bradykinin storm. Other studies have also emerged in recent weeks, showing that raising patients' vitamin D levels has a dramatic and beneficial effect on COVID-19 outcomes.
Vitamin D Massively Reduces ICU Admissions
Among them is a pilot randomized clinical study7,8,9 published online August 29, 2020, which found hospitalized COVID-19 patients in Spain 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 D10) followed by 266 mcg on Days 3 and 7 (equivalent to 53,200 IUs11). 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, and all were discharged without complications.
CDC Warns of Second Wave of COVID-19
In the video above, NBC News interviews Michael Osterholm, virologist and director of the Center for Infectious Disease Research and Policy at the University of Minnesota in Minneapolis, about the prospect of a second wave of COVID-19.
According to Osterholm, we likely have another 12 to 14 months of "a really hard road ahead of us." While Swedish statistics suggest the virus can and is dying off naturally, Osterholm believes cases will again rise as we move into fall and winter. Even if a vaccine does become available, it will take months to vaccinate the population, he notes.
Chief epidemiologist in charge of Sweden's coronavirus response, Anders Tegnell, has stated12 he does not believe Sweden will see a second wave with widespread contagion as the country is seeing a rapid decline in positive tests, indicating herd immunity is being achieved.13
That said, there are still open questions as to how long natural immunity might last.14 Some evidence points to months,15 while other data point to several years.16 Then there are the data suggesting herd immunity for COVID-19 occurs at much lower rates than normal.
As reported17 by Dr. James Hamblin in The Atlantic, infectious disease modeling by Gabriela Gomes, who specializes in nonlinear chaos dynamics, "selective depletion" of individuals susceptible to infection can rapidly reduce viral spread, and in the case of SARS-CoV-2, models suggest the threshold for herd immunity may occur below 20% of the population.
Yet other data18,19,20,21 suggest certain antibodies against other coronaviruses, such as the common cold, appear to provide some protection against SARS-CoV-2 as well, such that a majority of people may already have some level of immunity. So, there's a variety of "moving parts" that still need to be nailed down before we can come to any firm conclusions about future risks.