Vitamin D can protect against getting a severe case of COVID-19, a group of Swedish researchers and doctors have suggested in an article in the medical magazine Läkartidningen.

Given that known risk factors for COVID-19 are obesity, diabetes, and being institutionalised, low levels of vitamin D, which are dependent on sun exposure, are common to all of them, the doctors emphasised.

"Vitamin D deficiency increases the risk of a severe course of COVID-19. A metaanalysis of placebo-controlled studies shows that vitamin D treatment generally protects against respiratory tract infections. The effect is greatest in individuals with low vitamin D levels, which can be explained by the effect of the vitamin on the immune system", the researchers concluded.