AHS21

The decline in vitamin D status with indoor lifestyles is an example of the discordance hypothesis, wherein disease emerges because of the discordance between current and evolutionary environments. Vitamin D is a well-established immune factor and has a small but significant body of evidence favoring its usefulness in reducing the burden of upper respiratory tract infections, such as colds and flu. A large body of evidence emerged over the course of the COVID-19 pandemic suggesting that keeping vitamin D levels above 30 ng/mL might prevent most of the severity and mortality associated with the disease. However, some of those papers have had their authenticity questioned, and not every paper has arrived at the same conclusion. This presentation will review the literature to date on vitamin D and COVID-19 and provide an estimate of how protective it is and how confident we can be in its protection.