No Significant Association between 25-OH Vitamin D Status and SARS-CoV-2 Antibody Response after COVID-19 Vaccination in Nursing Home Residents and Staff

Abstract

Vitamin D is an essential nutrient for various physiological functions, including immunity. While it has been suggested that higher vitamin D levels/supplementation are associated with a better immune response to COVID-19 vaccination, conflicting data exist. Therefore, we aimed to investigate the association between vitamin D (25-hydroxyvitamin D) deficiency/supplementation, and SARS-CoV-2 antibody responses post-vaccination in nursing home residents (NHRs) and staff (NHS). Blood samples were collected from 115 NHRs and 254 NHS at baseline and 14 days after primary course BNT162b2 vaccination. Baseline samples were assessed for serum 25-hydroxyvitamin D levels, while follow-up samples were analyzed for spike protein S1 receptor-binding domain (S1RBD) IgG antibody concentrations and 50% pseudoneutralization titers. Vitamin D supplementation status was obtained from NHRs medical records. We compared immune responses between (severe) vitamin D-deficient and -sufficient NHRs/NHS and between supplemented and non-supplemented NHRs, stratified for history of SARS-CoV-2 infection and participant type. No significant differences in either binding or neutralizing COVID-19 vaccine antibody response were found between groups. The prevalence of vitamin D deficiency (<20 ng/mL) was 45% (95% CI: 36-54%) among NHRs and 60% (95% CI: 54-66%) among NHS. Although we showed that vitamin D status may not be related to a better COVID-19 vaccine antibody response, addressing the high prevalence of vitamin D deficiency in the nursing home population remains important.

Keywords: 25-hydroxyvitamin D; COVID-19 vaccination; SARS-CoV-2; nursing home residents; nursing homes; older adults; vitamin D.

Figure 1

S1RBD IgG antibody concentration (International Unit/mL) (A,B) and 50% pseudoneutralization titer (C,D) 14 days after BNT162b2 vaccination among 25-OH vitamin-D-deficient (<20 ng/mL) and 25-OH vitamin D sufficient (≥20 ng/mL) nursing home residents (A,C) and nursing home staff (B,D). Data is presented stratified for infection naïve participants (blue) and previously infected participants (red). Bold horizontal lines with error bars represent the geometric mean S1RBD IgG antibody concentration and median 50% pseudoneutralization titer per group with 95% confidence intervals. ns: not significant at the 0.05 level. Samples with a 50% pseudoneutralization titer of 0.00 were adjusted to a value of 0.01 in order to plot them on a logarithmic scale.

Figure 2

S1RBD IgG antibody concentrations (International Unit/mL) (A) and 50% pseudoneutralization titers (B) 14 days after BNT162b2 vaccination among vitamin D supplemented and non-supplemented nursing home residents. Data is presented stratified for infection naïve residents (blue) and previously infected residents (red). Bold horizontal lines with error bars represent the geometric mean S1RBD IgG antibody concentration and median 50% pseudoneutralization titer per group with 95% confidence intervals. ns: not significant at the 0.05 level. Samples with a 50% pseudoneutralization titer of 0.00 were adjusted to a value of 0.01 in order to plot them on a logarithmic scale.