Abstract 16608: A Randomized Study of Double-Dose versus Single-Dose Influenza Vaccination in Patients With Heart Failure
Background: Influenza infection leads to increased morbidity in those with heart failure, and we’ve previously shown that heart failure patients (HF pts) exhibit reduced antibody responses to influenza vaccine. We hypothesized that HF pts randomized to double dose influenza vaccine will mount more vigorous humoral immune responses compared to standard dose.
Methods: We randomized 28 HF pts stratified by age (> and < 70 years) to double dose (30mcg/mL) or standard dose (15mcg/mL) influenza vaccine. Per usual care, vaccine virus components were A/H3N2, A/H1N1, and B-type. Participants had phlebotomy prior to, at 2-4 weeks, and 4-6 months following vaccination to evaluate antibody production by hemagglutination inhibition assay (reported as log hemagglutination units, HAU).
Results: Baseline antibody titers between double dose (n=12, mean age 64±10) and standard dose (n=16, mean age 63±9) did not differ significantly. Compared to standard dose, the double dose group had higher initial antibody responses to the A/H3N2 vaccine virus (baseline to 2-4 week Δ 3.3±1.8 vs. 1.6±2.3 log HAU, p=0.04) and A/H1N1 (baseline to 2-4 week Δ 1.9±1.1 vs. 1.1±1.7 log HAU, p=0.06), but not to the B-type vaccine virus. However, by 4-6 weeks, there were no differences in titers in any of the virus types between treatment groups (figure).
Conclusions: While double dose influenza vaccine elicited higher A/H3N2 and A/H1N1 antibody responses initially compared to standard dose, differences were attenuated 4-6 months following vaccination during peak influenza season. These data suggest that antibody responses in HF patients wane even with higher initial doses of influenza vaccine, which may negate the potential benefit of this alternative vaccination strategy with greater potential for adverse effects.
- © 2011 by American Heart Association, Inc.