The results of a large study led by Army Gen. Brigham suggest that scientists need to continue investigating whether vitamin D supplements may have a long-lasting effect on the coronavirus. This study showed that taking high doses of vitamin D3 does not reduce the severity of COVID-19 infection, but may be associated with long-term COVID-19 outcomes. The results were published in the Journal of Nutrition.
“There has been a great deal of interest in whether vitamin D supplements have an effect on COVID-19, and this is one of the largest and most rigorous randomized trials on the subject,” said lead author Joan Manson, MD, PhD, of the General Brigham School of Medicine in Massachusetts. “Although we did not find that high doses of vitamin D reduced the severity of COVID-19 or hospitalization, we observed promising signs in the prolongation of COVID-19 that merit further study.”
VIVID Trial and Vitamin D Supplements
Vitamin D is often associated with immune health, but studies examining its role in COVID-19 have yielded mixed results. To uncover its potential benefits, researchers have launched a vitamin D trial against novel coronavirus disease (VIVID). This study assessed whether high-dose vitamin D3 supplementation could affect outcomes for people recently diagnosed with COVID-19 and their families.
The study included participants from both the United States and Mongolia. In total, 1,747 adults who had recently tested positive for COVID-19 and 277 household contacts were randomly assigned to receive either vitamin D3 or a placebo daily for four weeks. The supplementation protocol used vitamin D3 (9,600 IU/day for 2 days, then 3,200 IU/day).
The U.S. portion of the trial was conducted from December 2020 to September 2022, and the Mongolian study was conducted from September 2021 to April 2022. On average, participants started taking vitamin D supplements or a placebo about three days after testing positive for coronavirus.
Ensuring a balanced study group
Along with Manson, first authors Davaasambu Gummer, Caitlin Cook, and colleagues used stratified randomization and statistical weighting to balance factors known to influence COVID-19 outcomes, such as age, gender, body mass index, race/ethnicity, and COVID-19 vaccination status, between the two groups.
The severity and infectivity of the new coronavirus will not improve.
Over the four-week study period, researchers found no significant differences between the vitamin D and placebo groups in terms of medical utilization or mortality. Healthcare utilization includes hospitalization, in-person or online clinic visits, and emergency room visits. Symptom severity was also similar in both groups.
Taking high-dose vitamin D supplements did not reduce the likelihood of household contacts contracting the coronavirus.
Possible signal that long-term symptoms of new coronavirus may be alleviated
When researchers analyzed participants who consistently followed a vitamin D regimen, they noticed potential signals associated with long-lasting coronavirus. These people appeared to be slightly less likely to report persistent symptoms eight weeks after infection compared to those who received a placebo.
Among participants taking vitamin D, 21% reported at least one lingering symptom, compared with 25% in the placebo group. This difference was considered to be borderline statistically significant.
“Prolonged exposure to COVID-19, which can include symptoms such as fatigue, shortness of breath, brain fog and other cognitive issues, continues to have a major impact on people’s lives,” Munson said. “We hope to conduct further studies in larger populations to determine whether long-term vitamin D supplementation reduces the risk and severity of long-term COVID-19 infection.”
Author and disclosure information
Authors: In addition to Manson and Gummer, authors of Mass General Brigham include Alison Klar, Michael Rushman, Aditi Hazra, Howard D. Sesso, Valerie E. Stone, Patricia Copeland, and Georgina Friedenberg. Other authors include Cook, Polyna Khudyakov, Dorjbal Enkhjargal, Tsolmon Bilegtsaikhan, Kenneth H. Mayer, Raji Balasubramanian, Douglas C. Smith, Quanhong Lei, Todd Lee, Emily G. McDonald, Tserenkhuu Enkhtsetseg, Erdenebaatar Sugar, Yansanjav Narankhuu, Myagmarsuren Contains. Erdenetja, Daruk Tserendagva, Rikard Lundberg, Niklas Roxhead, Suzanne Rautiainen.
Disclosure: Roxhed is the founder and shareholder of Capitainer AB, a company that commercializes the blood collection device used in this study. All other authors declare no conflicts of interest.
Funding: This research received anonymous foundation support and philanthropic support from John Sabes, Minneapolis, MN. The authors also acknowledge support from Tishcon Corporation, which donated research capsules of vitamin D and placebo. Takeda; and the captain card. The authors declare no specific grant for this research from any funding agency in the public, commercial, or not-for-profit sectors.
