Vitamin D and immune response against severe acute respiratory syndrome coronavirus 2 in older adults: does it really work?

Coronavirus disease 2019 was announced as a pandemic by the WHO on 11 February 2020. Since that time, challenges have arisen regarding the use of supplements to optimally support the immune system in the general population, and especially in older adults. The severity of severe acute respiratory syndrome coronavirus 2 infection varies significantly with age, being generally more severe in geriatric patients. There is evidence supporting the involvement of vitamin D in different processes related to the immune response. Some observational studies have related the decrease in vitamin D levels to the severity of coronavirus disease 2019, suggesting a protective role of vitamin D in this disease. In this narrative review, we analyze the possible role of vitamin D in modulating the immune mechanisms that are activated during severe acute respiratory syndrome coronavirus 2 infection, with special emphasis on older adults. Copyright (c) 2022 Wolters Kluwer Health, Inc. All rights reserved.