In a Mendelian randomization study, researchers found no genetic evidence to support an association between Vitamin D levels and COVID-19 susceptibility, severity, or hospitalization.

Vitamin D and COVID-19 susceptibility and severity in the COVID-19 Host Genetics Initiative: A Mendelian randomization study – PLOS Medicine

Commentary: Vitamin D may not provide protection from COVID-19 susceptibility or disease severity, study suggests – PLOS

Related: Living systematic review: The evidence is insufficient to determine the benefits and harms of vitamin D supplementation as a treatment of COVID‐19. AND RCT: Vitamin D3 does not improve outcomes in hospitalized patients with moderate to severe COVID-19