雖然目前已有多種SARS-CoV-2疫苗研發出來且已展開大規模接種，但變種病毒株也陸續出現。現有的疫苗是否能有效地對抗COVID-19變種病毒株，仍屬未知數。臨床實證支持維生素D的基本藥理作用及功效，應可考量作為對抗COVID-19的重要輔助治療選項之一。臨床實證顯示：血中25(OH)D濃度與罹患COVID-19感染風險及其死亡率呈現顯著負相關性；而補充巨量(mega-dosages)維生素D以快速地提升病患的血中25(OH)D濃度，則有助於患者的病毒核酸檢測轉為陰性，並且預防或輔助治療COVID-19引起的多重併發症。

The mass vaccination campaigns have been implemented after COVID-19 vaccines were authorized under the emergency use authorization (EUA). However, new SARS-CoV-2 variants continue to emerge. It remains unknown whether current vaccines are effective against these variants. Clinical evidence supports vitamin D as an essential therapeutic agent in COVID-19. Serum 25(OH)D levels are inversely correlated with COVID-19 infection and mortality. Vitamin D administration with mega-dosages could quickly increase serum 25(OH)D concentrations and decrease SARS-CoV-2 titers. In addition, COVID-19 related complications could be prevented or treated by vitamin D therapy.