title: Double dose vs. standard dose influenza vaccination in patients with heart failure: a pilot study.
abstract: OBJECTIVE
  Influenza infection leads to increased morbidity and mortality in those with heart failure, and individuals with heart failure exhibit reduced antibody responses to influenza vaccine. We hypothesized that patients with heart failure randomized to double dose (DD) influenza vaccine will mount more vigorous humoral immune responses compared with those given standard dose (SD) vaccine.
  
  
  RESULTS
  We randomized 28 heart failure patients to DD (30 μg/strain) or SD (15 μg/strain) influenza vaccine. We assessed antibody production by haemagglutination inhibition assay (reported as log haemagglutination units) prior to, at 2-4 weeks and at 4-6 months following vaccination. Baseline antibody titres between DD (n = 12, mean age 64 ± 10 years) and SD (n = 16, mean age 63 ± 9 years) did not differ significantly. At 2-4 weeks, DD haemagglutination unit changes were significantly higher than those of SD (3.3 vs. 1.6 for A/H3N2, P < 0.001; 1.9 and 1.1 for A/H1N1, P = 0.009; and 1.7 and 1 for B-type, P = 0.02). At 4-6 weeks, there were no differences in titres in any of the virus types between treatment groups and, although titres decreased, levels remained above the seroprotective threshold.
  
  
  CONCLUSIONS
  Higher influenza vaccine doses may elicit increased antibody-mediated responses in patients with heart failure; further studies should assess whether clinical outcomes are improved with this strategy.
authors.affiliation: School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Van Ermen
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Hermanson
authors.forename: John M
authors.initials: JM
authors.lastname: Moran
authors.forename: Nancy K
authors.initials: NK
authors.lastname: Sweitzer
authors.forename: Maryl R
authors.initials: MR
authors.lastname: Johnson
authors.forename: Orly
authors.initials: O
authors.lastname: Vardeny
mesh_terms: D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D004306:Dose-Response Relationship, Immunologic; D004311:Double-Blind Method; D005260:Female; D006333:Heart Failure / Q000276:immunology*; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D056724:Immunity, Humoral; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D009981:Influenza B virus / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D014611:Vaccination
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines