Lastly, we identified good binding activities of vitamin D with the 5R84 structure in COVID-19, the 3RGK structure in the target MB and the 2WR6 structure in the target RBP4 through molecular docking analysis, suggesting that vitamin D can effectively bind to specific proteins associated with SARS-CoV-2, and that vitamin D may be able to act on the MB and RBP4 to target COVID-19. Here, RBP4 is linked to COVID-19.