Seroresponse to Inactivated and Recombinant Influenza Vaccines among Maintenance Hemodialysis Patients

Rationale & Objectives High dose influenza vaccine provides better protection against influenza infection in older adults than standard dose vaccine. We compared vaccine seroresponse among hemodialysis patients over 4 months after high dose inactivated (HD-IIV3), standard dose inactivated (SD-IIV4) or recombinant (RIV4) influenza vaccine. Study Design Prospective observational study. Setting & Participants Patients at four hemodialysis clinics who received influenza vaccination. Hemagglutination inhibition titers were measured at baseline and at 1, 2, 3 and 4 months following vaccination with HD-IIV3, SD-IIV4 or RIV4 influenza vaccine. Outcome The primary outcome was seroprotection rates at ≥1:40 and ≥1:160 (which correspond to antibody levels providing protection from infection in about 50% and 95% immunocompetent individuals, respectively) at 1, 3 and 4 months after vaccination. Analytical approach We determined GMT and seroprotection and seroconversion rates. Chi-square or Fisher exact tests were used for categorical data; continuous values were analyzed using Wilcoxon rank-sum tests. Generalized estimating equation was used to determine association between GMT and age. Results 254 HD patients received HD-IIV3 (n=141), SD-IIV4 (n=36) or RIV4 (n=77) vaccine. A robust initial seroresponse to influenza A strains was observed after all 3 vaccines, with no difference in seroprotection rates at either the ≥1:40 or ≥1:160 titer at 1 and 2 months. Seroresponses to RIV4 and SD-IIV4 waned thereafter, such that by month 3 and 4, seroprotection by HD-IIV3 was significantly higher. Seroprotection rates were lower to the B strains across all three vaccines. Results trended similarly across patients aged below 65 years. Limitations Due to use of observational data, bias by unmeasured confounders may exist. Some of the subgroups by age were low in number. Conclusions Hemodialysis patients achieved high seroprotection rates after all 3 vaccines. The seroresponse waned more slowly with HD-IIV3 as compared to SD-IIV4 or RIV4 vaccine.