The Older Population's Antibody Response to SARS-CoV-2 Inactivated Vaccine (CoronaVac) is Independent to Vitamin D Levels

Objective: The purpose of this study was to determine how the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) inactivated vaccine antibody response and vitamin D levels in the older population are related. Materials and Methods: This study included people over the age of 60 who received their second dose of the SARS-CoV-2 inactivated vaccine after 28 days. Immunoglobulin G antibodies against SARS-CoV-2 spikes were measured; levels equal to or greater than 1 U/mL were classified as seropositive, and levels below 1 U/mL were classified as seronegative. Serum 25-hydroxyvitamin D levels were evaluated in the participants; levels below 30 nmol/L were classified as low, and levels above 30 nmol/L were classified as normal. Results: A total of 188 patients were included. A total of 152 people (80.9%) were found to be positive for the antibodies. The median [interquartile range (IQR)] age of the seropositive individuals was 71 (60-94) and the median (IQR) age of seronegative individuals was 72 (64-86) (p=0.272). While the vitamin D level was below 30 in 115 (75.6%) of the seropositive group, the vitamin D level was below 30 in 26 (70.9%) patients in the seronegative group (p=0.822). Conclusion: In this study, we examined the association between vitamin D levels and seroconversion rate after the second dose of SARS-CoV-2 inactivated vaccine. There were no differences between the seropositive and seronegative groups in terms of vitamin D levels. In another context, it was discovered that vitamin D level has no effect on antibody response.