Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) disease (COVID-19) has affected many people. Vaccination and masks have significantly reduced the morbidity and mortality of the disease. Vitamin D (VitD) and its effects on infections from viruses have been of interest. Many athletes have low serum levels of VitD (1). VitD plays a vital role in an athlete's health, training, and performance (2). The vital role includes athletic bone health, besides immune health (3).The antimicrobial protein, cathelicidin LL-37, is increased with correction of low VitD over 6 to 8 wk. Cathelicidin exerts antiviral activity against respiratory viruses, disrupting the viral envelope (4). VitD has received notoriety as potentially protective against the COVID-19 infection since it may be associated with immunocompetence, inflammation, aging, and other diseases connected to the outcomes of COVID-19. In the Nurses' Health Study II, performed from May 2020 to 2021, they shoulder evidence that higher predicted circulating VitD, in the form of VitD 25 hydroxy concentration, had a lower risk of . In a review of COVID-19 and VitD, the author showed that people with low VitD levels have more severe COVID-19 symptoms than those with serum levels over 50 ng•mL −1 of VitD (6). People with low VitD are not the healthiest patients, so they may get sicker with COVID-19.Researchers have pointed out that VitD does not work without binding to the VitD receptor (VDR) and VitD binding protein (DBP). The activated immune system cells express the intracellular VDR, which suggests a potential role for VitD as a localized endogenous modulator of immune function. In addition, VDR has genetic variations that may affect the responsiveness to VitD levels. DBP, a serum 458-amino acid protein, is the primary VitD carrier. It has considerable polymorphism with three common alleles (7). Researchers have noted that DBP-2 can have lower VitD, which may make certain patients more prone to a more severe course of . Another researcher noted a negative connection between another version of DBP, the DBP1 allele, and COVID-19 prevalence and mortality (9). More research on VDR and DBP is needed to determine their effects on COVID-19 and other health processes.