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Vitamin D Supplementation and COVID-19 Survival by Dr Carissa Doherty, ND

As of April 27, 2021, over 3 million deaths from COVID-19 have been confirmed.

The researchers of this study titled “Vitamin D and Survival in COVID-19 patients: A Quasi-experimental Study”, theorized that vitamin D may improve COVID-19 adverse outcome by 1) regulating the renin-angiotensin system (RAS), 2) the innate and adaptive cellular immunity, and 3) improving immune physical barriers.

This study highlighted the previous research that showed hypovitaminosis D is more common from October to March at northern latitudes and that those latitudes experienced the highest lethality rates of COVID-19 in winter of 2020.

Dr Cédric Annweiler, MD, PhD, and his research team noted other research that observed an inverse association between low vitamin D levels in serum and the number of COVID-19 cases as well as with COVID-19 mortality.

The design of this research study was to see if an association of vitamin D3 supplementation and COVID-19 mortality existed in a group of elderly residents in nursing home who were infected with SARS-Co-V-2. The aim of the research study was to determine if a large dose of vitamin D supplementation taken during or just before COVID-19 improved survival of these residents. And the second aim was to evaluate the effectiveness of the vitamin D supplementation in improving the severity of infection.

The study population was residents at a mid-sized nursing home in Rhône, South-East of France. These residents were significantly impacted by COVID-19 in March-April 2020: 96 patients contracted the virus.

The actual study intervention was based on the residents receiving a single oral dose of 80,000IU vitamin D3. The intervention group was defined as all COVID-19 residents who received their oral dose of vitamin D either in the week following the suspected or diagnosis of COVID-19 or during the previous month. The comparator group corresponded to all other COVID-19 residents who did not receive any recent vitamin D supplementation.

Vitamin D3 supplementation was associated with 68% lower mortality. Results showed a 17.5% mortality in the intervention group vs 55.6% mortality in the control group.


This study concluded that bolus vitamin D3 supplementation during or just before COVID-19 was associated to less severe COVID-19 and better survival rate in frail elderly.


Annweiler, C., et al., Vitamin D and survival in COVID-19 patients: A quasi-experimental study. J Steroid Biochem Mol Biol, 2020. 204: p. 105771.