Immunological Response to SARS-CoV-2 Is Sustained by Vitamin D: A Case Presentation of One-Year Follow-Up

Vitamin D is necessary for normal bone development and conservation. Moreover, it has extraskeletal effects, which play a pivotal role as a modulator of innate and adaptive immune responses. Many studies have highlighted the beneficial effect of vitamin D in protecting against acute respiratory viral infection, including COVID-19. Within this context, we described the effect of vitamin D supplementation in the immunological response to SARS-CoV-2 infection. Long-term IgG SARS-CoV-2 antibody responses were assessed in a cohort of twenty-two subjects diagnosed with COVID-19 by chemiluminescence assay (CLIA). Among them, a 61-year-old nurse undergoing vitamin D therapy showed a positive IgG response against SARS-CoV-2 nucleocapsid over nine months after infection, suggesting vitamin D played a role in modulating early antibody response against SARS-CoV-2. This result provides evidence of a positive effect of vitamin D on the decrease of functional humoral immunity.