title: Humoral response to the influenza A H1N1/09 monovalent AS03-adjuvanted vaccine in immunocompromised patients.
abstract: BACKGROUND
  Few data are available regarding the immunogenicity and safety of the pandemic influenza vaccine in immunocompromised patients. We evaluated the humoral response to the influenza A H1N1/09 vaccine in solid-organ transplant (SOT) recipients, in patients with human immunodeficiency virus (HIV) infection, and in healthy individuals.
  
  
  METHODS
  Patients scheduled to receive the pandemic influenza vaccine were invited to participate. All participants received the influenza A H1N1/09 AS03-adjuvanted vaccine containing 3.75 μg of hemagglutinin. SOT recipients and HIV-infected patients received 2 doses at 3-week intervals, whereas control subjects received 1 dose. Blood samples were taken at day 0, day 21, and day 49 after vaccination. Antibody responses were measured with the hemagglutination inhibition assay (HIA) and a microneutralization assay.
  
  
  RESULTS
  Twenty-nine SOT recipients, 30 HIV-infected patients, and 30 healthy individuals were included in the study. Seroconversion measured by HIA was observed in 15 (52%) of 29 SOT recipients both at day 21 and day 49; in 23 (77%) of 30 at day 21 and 26 (87%) of 30 at day 49 in HIV-infected patients, and in 20 (67%) of 30 at day 21 and in 23 (77%) of 30 at day 49 in control subjects (P = .12 at day 21 and P = .009 at day 49, between groups). Geometric means of antibody titers were not significantly different between groups at day 21 or at day 49.
  
  
  CONCLUSIONS
  Influenza A H1N1/09 vaccine elicited a similar antibody response in HIV-infected individuals and in control subjects, whereas SOT recipients had an overall lower response. A second dose of the vaccine only moderately improved vaccine immunogenicity in HIV-infected patients.
authors.affiliation: Transplantation Center, Infectious Diseases Service, University Hospital of Lausanne (CHUV) and University of Lausanne, Switzerland. oriol.manuel@chuv.ch
authors.forename: Oriol
authors.initials: O
authors.lastname: Manuel
authors.forename: Manuel
authors.initials: M
authors.lastname: Pascual
authors.forename: Katja
authors.initials: K
authors.lastname: Hoschler
authors.forename: Stefano
authors.initials: S
authors.lastname: Giulieri
authors.forename: Deolinda
authors.initials: D
authors.lastname: Alves
authors.forename: Kim
authors.initials: K
authors.lastname: Ellefsen
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Bart
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Venetz
authors.forename: Thierry
authors.initials: T
authors.lastname: Calandra
authors.forename: Matthias
authors.initials: M
authors.lastname: Cavassini
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000328:Adult; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D004338:Drug Combinations; D005260:Female; D015658:HIV Infections / Q000276:immunology; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods; D016867:Immunocompromised Host; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009500:Neutralization Tests; D016377:Organ Transplantation; D011136:Polysorbates / Q000008:administration & dosage*; D013185:Squalene / Q000008:administration & dosage*; D014611:Vaccination / Q000379:methods; D024502:alpha-Tocopherol / Q000008:administration & dosage*
chemical_list: D000276:Adjuvants, Immunologic; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D004338:Drug Combinations; D007252:Influenza Vaccines; D011136:Polysorbates; D013185:Squalene; C550253:AS03 adjuvant; D024502:alpha-Tocopherol