Steve M. Gaskin, MD, in his article “Supplements for Treating COVID-19” outlines some basic research in biological mechanisms for zinc, vitamin D, and melatonin, and then asks whether we should wait for appropriate studies or adopt early for some level of cost-benefit with few side effects. (EMN. 2020;42:31; https://bit.ly/34iJW3F.)
Dr. Gaskin's excellent question and our dilemma, especially as it relates to all things COVID-19, is outlined diagrammatically in “Sensible Medicine—Balancing Intervention and Inaction during the COVID-19 Pandemic.” (JAMA. 2020;324:1827; https://bit.ly/2IwUk0c.)
But a few comments about what should not be assumed by Dr. Gaskin's question:
- Biological mechanism is a long distance from the finish line of clinical importance, and small, poorly done observational trials are just an early water station.
- We do have appropriate evidence-based clinical studies that suggest that vitamin D supplementation in healthy people over 70 does nothing to decrease infections (n=2157, three years, five countries, double-blind, placebo-controlled; JAMA. 2020;324:1855.)
- Zinc does not have few side effects, but may decrease or change taste and can be an immunosuppressant, especially of T cells. Neither of these would seem advisable in those trying to prevent or treat COVID-19.
But there is a final, perhaps more opaque, reason none of us should recommend zinc, vitamin D, or melatonin to prevent COVID-19 or even to treat it in most cases, apart from the fact that none of them has strong clinical studies to support their role in infection, including COVID-19. Trying something that is not proven clinically with good strong science in a relatively healthy person (who is not about to immediately die) breeds a dangerous medical environment that has crippled our culture, even before 2020, in which hot political buttons and social topics gone viral get way ahead of the slow arduous pendulum-swinging of scientific studies and their opposing arguments.
The what-can-it-hurt philosophy of zinc-vitamin D-melatonin is from the same graduating class as chloroquine-azithromycin-hydroxychloroquine and many more to come. By acquiescing to this can't-wait-can't-hurt philosophy, medical science becomes subservient to popular electronic opinion. That cultural malady is already infecting and spreading throughout our profession.
Mark Mosley, MD, MPH