Vitamin D supplementation found to reduce COVID-19-related mortality, says study

As the coronavirus disease 2019 (COVID-19) pandemic evolves, many agents have been tested to see if they can reduce the risk of severe disease and death among infected patients. One of the widely explored agents that have been shown to reduce disease progression is vitamin D.

Caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19 is primarily a respiratory illness but is known to affect other parts of the body, from the gastrointestinal tract to the central nervous system. It can also overwhelm the immune system in severe cases, hence the scientific interest in whether immune-boosting supplementation can help fight off the infection.

Researchers at the Tabriz Health Services Management Research Center, Tabriz University of Medical Sciences, and the Shahid Beheshti University of Medical Sciences showed that prescribing vitamin D supplementation to COVID-19 patients seems to decrease the mortality rate, the severity of the disease, and serum levels of inflammatory markers.

Vitamin D and COVID-19

The coronavirus pandemic has spread to 191 countries and regions, with over 86.47 million cases and 1.86 million deaths. With the global spread of the SARS-CoV-2 and rise in infection and mortality toll, efficient management of the illness has become an absolute priority.

Many scientists have since studied various agents to determine those that can prevent disease progression and COVID-19-related death. Several studies have suggested the positive impact of vitamin D on COVID-19 patients.

Vitamin D is a fat-soluble micronutrient that could facilitate the function of the immune system. In the past, studies have shown the potential link between vitamin D deficiency and severe outcomes in COVID-19 patients

This systematic review aims to evaluate the effects of vitamin D supplementation on clinical outcomes and mortality rate of COVID-19 patients.

Even before the current pandemic, the immunomodulatory role of vitamin D has been studied in the treatment of other upper respiratory infections. Vitamin D can help regulate the immune system, thanks to receptors found in various innate immune system cells. The vitamin can also suppress the adaptive immune response in the affected lung epithelial cells, hence, preventing the pro-inflammatory agents' harm on the affected sites.  

Lastly, vitamin D plays an important role in protecting against the direct damage of the inflammatory factors, which are released during viral diseases.

The study

The study, published on the pre-print medRxiv* server, highlights the role of vitamin D supplementation in reducing the risk of severe illness and death due to COVID-19.

The team conducted a systematic review to arrive at the study findings, including research from PubMed, Web of Knowledge, Scopus, Embase, The Cochrane Library, and Ovid up to December 16, 2020.

The team has found that in three of the studies, the survival and mortality rate of the patients were studied, revealing that a significantly lower mortality rate among the intervention groups compared to the control groups. Moreover, two of the studies showed that the clinical outcomes based on the World Health Organization (WHO) Ordinal Scale for Clinical Improvement (OSCI) score for COVID-19, were lower in patients who received vitamin D supplementation.

Further, a study showed that there is a lower rate of intensive care unit (ICU) admission among those who received vitamin D, and another study reported a marked decrease in serum levels of fibrinogen, which increases in levels in any condition that causes inflammation or tissue damage.

Vitamin D supplementation seems to decrease the mortality rate, the severity of the disease, and the inflammatory markers' levels among the COVID-19 infected patients, leading to a better prognosis and increased survival… More studies should be conducted to determine the optimum dosage and route of vitamin D supplementation and further investigate the potential prophylactic effects."

To date, many countries report surging COVID-19 cases, including the United States and the United Kingdom, with over 21 million and 2.78 million cases, respectively. Since October 2020, the UK has experienced a second wave of the pandemic, with a new variant that is thought to be around 70% more infectious now circulating.

Knowing more about potential therapies to reduce the risk of death tied to COVID-19 is important as the world waits for the full deployment of COVID-19 vaccines.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:
Angela Betsaida B. Laguipo

Written by

Angela Betsaida B. Laguipo

Angela is a nurse by profession and a writer by heart. She graduated with honors (Cum Laude) for her Bachelor of Nursing degree at the University of Baguio, Philippines. She is currently completing her Master's Degree where she specialized in Maternal and Child Nursing and worked as a clinical instructor and educator in the School of Nursing at the University of Baguio.


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  1. Larry Jessip Larry Jessip United States says:

    Just my experience with Vit. D and Covid 19.  In Feb 2020 for a completely unrelated problem my urology dr. did a test for my Vit. D levels and found them low.  He proscribed 50,000 IU Vit. D2 pills at once a week for 2 months and once a mo. following.  In April I had a case of Covid toe. Middle toe on each foot turned black. Looked like Gangrene actually.  But then they came out of it.  I think the Vit. D supplement stopped the Covid before it became severe.  

    Also in December one morning I woke up and stumbled into the kitchen for breakfast and realized after a few bites I had no sense of taste or smell. Everything was bland. So figuring it was a early Covid symptom I took one of the last D2 supplements I had.  At lunchtime I was fine.   I suspect myself that megadoses of Vit. D slow down or stop outright the virus,

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