Vitamin D and Covid: a lead, not proof

A study published in Scientific Reports, the Nature group’s open-access journal, followed US veterans and counted fewer infections and fewer deaths among those who had been prescribed vitamin D. The detail matters, because the two forms do not give the same result: with D3, the common form, 20% fewer infections and 33% fewer deaths within thirty days of infection; with D2, 28% fewer infections, but a drop in mortality that does not reach statistical significance.

The authors write that these are associations, and that a randomised trial would be needed to conclude anything. They list themselves what could explain the gap otherwise: people who take supplements see a doctor more often and protect themselves more, and neither weight nor income was accounted for.

This is an open-access article published on 12 November 2022 in Scientific Reports, brought to my attention via Dr John Campbell’s YouTube channel.