Vitamin D, influenza vaccine response, and respiratory illness

Background There is evidence that vitamin D (vit D) affects immunity and response to infection. The objective of this study was to determine whether serum vit D predicts influenza vaccine response or upper respiratory illness (URI). Methods 1101 adults ≥ 50 years old were recruited from 2 communities in WI and TN during the 2008–2009 and 2009–2010 flu seasons. Pre‐and post‐vaccination hemagglutinin antibody inhibition (HAI) titers to vaccine components and serum vit D (1,25(OH) 2 D) were measured. Seroprotection was defined as HAI ≥ 40; seroconversion as ≥ 4‐fold increase in post‐vaccination HAI. ARI was assessed by self‐report. Results Mean (± SD) serum vit D was 31 ± 10 ng/mL; 28.5% participants were vitamin D deficient (VDD). Vit D and VDD did not predict seroconversion for any vaccine components in 08–09 (odds ratio [OR]: 95% confidence interval [CI] 1.00: 0.98–1.01, 1.00: 0.98–1.02, and 1.01: 0.99–1.03) for H1N1, H3N2 and B subtypes, respectively (controlling for age, gender, and pre‐vaccination HAI). Vit D did not predict seroconversion in 09–10 or seroprotection or ARI in either year. VDD was related to physician‐attended URI (p = 0.01) but no other disease outcomes in year 1. Conclusions There was no consistent relationship between vit D and response to influenza vaccination or respiratory illness in our population. Funding Source: CDC 5 U18 IP000183 ‐02, CDC 1 U18 IP000184 ‐01, K23 A1074863‐01A1 (Talbot)