As the COVID-19 pandemic continues to spread and mutate, researchers are working tirelessly to better understand the virus, its variants, and its effects. As highly resistant strains continue to take their toll, researchers and doctors look for new angles from which to combat the continued spread of COVID-19 and treat suffering patients.

One answer for improved COVID-19 treatment might actually be found in the sun. More specifically, in Vitamin D.

COVID-19 and Vitamin D Deficiency

A recent study published in the European Review for Medical and Pharmacological Sciences assessed the potential link between vitamin D deficiency and acute COVID-19 infection by studying patients who had recovered from the virus. An anecdotal connection between COVID-19 and Vitamin D had been established by doctors and researchers early in the pandemic, and COVID-19 research not specific to Vitamin D had verified such a link, but there had been very limited formal work done on the matter of COVID-19 and Vitamin D specifically prior to this study.

The methodology of the study relied on ELISA (enzyme-linked immunosorbent assay) testing to measure the presence of COVID-19 antigens. An ELISA test kit is a robust and versatile tool for detecting and measuring the presence of many different antibodies in a blood sample. ELISA can be adapted to just about any immune system condition so long as scientists are able to develop a reliable antigen enzyme for binding to the antibody being detected. ELISA testing has improved understanding of COVID-19 response for many health systems and can help researchers reliably detect COVID-19 variants.

Over 200 post-COVID-19 patients were tested over the course of the study, and an astonishing 84% of them were found to have deficient Vitamin D levels, defined here as less than 20 ng/dL. Another 11% were in the range of 20 to 30 ng/dL, which is considered insufficient. Less than 5% of patients were tested to have normal Vitamin D levels.

Interestingly, no substantial link was found between Vitamin D deficiency and actual post-COVID-19 symptoms, either acute or long-term, in the course of this study. The study’s authors concluded by encouraging further research into the link between Vitamin D and COVID-19.

A systematic meta-analysis of the data available to date was also published in November of 2020 and verified the link between COVID-19 and Vitamin D deficiency through a variety of sources, several of which used ELISA testing to validate the presence of COVID-19. Several medical databases were exhaustively searched for relevant cases, and the researchers observed a demonstrable link between low Vitamin D levels and the severity of COVID-19 cases. The review further links low Vitamin D to COVID-19 mortality rates.

Given these studies, it is reasonable to posit that healthy Vitamin D levels could be beneficial for the prevention or treatment of COVID-19. Most of the Vitamin D absorbed by humans comes directly from natural sunlight, so this link may provide an answer to the mystery of why countries near the equator appear to experience a lower rate of COVID-19 mortality despite similar rates of infection.

It is important to note that Vitamin D is far from the only factor, or even the greatest factor, impacting COVID-19 mortality rates. Other extenuating circumstances that make severe or fatal COVID-19 more likely include:

  • Respiratory illness
  • Heart conditions
  • Obesity
  • Hypertension

Some of these factors are also implicated in low Vitamin D levels, however. This further complicates the work of unraveling all the connections between Vitamin D, COVID-19, and overall health.