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A new large multi-center cross-sectional study found treatment with high-dose vitamin D (either weekly or daily) was associated with reduced COVID-19 mortality.
Multi-dose clinical trials need to be carried out to determine vitamin D efficacy. 1/7 https://www.mdpi.com/2072-6643/12/12/3799/htm
Multi-dose clinical trials need to be carried out to determine vitamin D efficacy. 1/7 https://www.mdpi.com/2072-6643/12/12/3799/htm
Trials testing dose and frequency are important. Frequency is important because other randomized controlled trials have shown that weekly & daily vitamin D doses were protective against respiratory infections but not monthly doses (ie. a single dose). 2/7 https://www.bmj.com/content/356/bmj.i6583
The dose is also important because there are low responders. In a sample of 35 healthy people given 8,000 IU of vitamin D, there were 14 high, 11 mid, and 10 low responders. There is a huge inter-individual variation to vitamin D supplementation. 3/7 https://www.sciencedirect.com/science/article/abs/pii/S096007601630173X?via%3Dihub
Keeping what I said in mind, a new small randomized controlled trial showed no clinical benefit for a single high dose of vitamin D3 in COVID-19 patients. But as I mentioned single doses of vitamin D do not always work and other problems include... 4/7 https://jamanetwork.com/journals/jama/fullarticle/2776738
Patients were given vitamin D 10 days after symptom onset. They were very sick and were given many other treatments including dexamethasone. It is very difficult to measure any additional effects of vitamin D over other treatments, particularly with a small sample size. 5/7
A randomized controlled trial to investigate the prophylactic use of vitamin D for reducing COVID-19-associated hospitalization and mortality (VIVID trial) is underway and is still recruiting participants. See info below... 6/7 https://clinicaltrials.gov/ct2/show/NCT04536298
This type of trial may be the best hope for proving the clinical benefit of vitamin D in COVID-19. Hospital-based treatment trials are challenging since patients are very sick and it may be too late for vitamin D to protect. 7/7 https://www.sciencedirect.com/science/article/pii/S1551714420302548