Previous Vaccination and Age are More Important Predictors of Immune Response to Influenza Vaccine than Inflammation and Iron Status in Dialysis Patients.

BACKGROUND/AIMS The immune response to influenza vaccine may be influenced by many factors, e.g. age, comorbidities or inflammation, and iron status. METHODS We studied the vaccine-induced production of hemagglutination-inhibition antibodies (HI) in 133 hemodialysis patients (HD) and 40 controls. To identify variables associated with the immune response, uni- and multivariate regression analyses were performed with seroconversion in HI titers as a dependent variable, with demographics, comorbidities, previous vaccination, inflammation, and iron status as independent variables. RESULTS Seroconversion rates were lower in HD than in controls [43% versus 73% (H1N1 strain; p < 0.05); 43% versus 53% (H3N2; P=NS); 36% versus 62% (B; p < 0.05)]. In both HD and control groups, the predictors of the inferior HI production were pre-vaccination seroprotection, vaccination in the previous season, and old age. We did not find associations between seroconversion rates and inflammation and iron status in the studied populations. This was also true for a subanalysis of patients without pre-vaccination seroprotection. CONCLUSION The influenza vaccine-induced antibody production was lower in HD than in controls and was independent of inflammation and iron status in both groups. Besides dependence on dialysis, the variables associated with inferior seroconversion rates included pre-vaccination seroprotection, previous vaccination, and old age.