Serious Data Issues at Play in a Randomized Trial of Vitamin D for Covid-19

A major trial of vitamin D treatment for Covid-19 has a number of flaws that make the results unreliable

Pictured: Probably fish oil, but that’s what you get when you search “supplement” on stock photo websites. Photo by Leohoho on Unsplash

One of the bigger questions throughout the pandemic has been whether vitamin D supplements are a useful tool in preventing and treating Covid-19. Since early 2020, people have been constantly wondering whether taking some extra vitamin D would help them fight off the dreaded spicy cough.

Stock photos for “spicy cough”, on the other hand, deliver amazingly well. Photo by Fernando Andrade on Unsplash

There have, at this point, been dozens of studies published attempting to answer the question of whether vitamin D works for Covid-19. Of these, one of the most influential has been a medium-sized randomized controlled trial from a group in Hyderabad. The study found that there was a massive improvement in people given vitamin D compared to a control group in terms of their inflammation caused by Covid-19.

This paper has been read by more than 100,000 people, cited academically dozens of times, appears in numerous media reports, and generally has had a big impact on the question of whether vitamin D supplements are effective as a treatment for…