Does Vitamin D Protect Against COVID-19?

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This transcript has been edited for clarity.

Hello. This is Dr JoAnn Manson, professor of medicine at Harvard Medical School and Brigham and Women's Hospital.

I'd like to talk with you about vitamin D and COVID-19. Is there potentially a protective role?

We've known for a long time that it's important to avoid vitamin D deficiency for bone health, cardiometabolic health, and other purposes. But it may be even more important now than ever. There's emerging and growing evidence that vitamin D status may be relevant to the risk of developing COVID-19 infection and to the severity of the disease.

Vitamin D is important to innate immunity and boosts immune function against viral diseases. We also know that vitamin D has an immune-modulating effect and can lower inflammation, and this may be relevant to the respiratory response during COVID-19 and the cytokine storm that's been demonstrated.

There are laboratory (cell-culture) studies of respiratory cells that document some of these effects of vitamin D. There's also evidence that patients with respiratory infections tend to have lower blood levels of 25-hydroxy-vitamin D.

There's now some evidence from COVID-19 patients as well.