title: Immunogenicity of a monovalent 2009 influenza A (H1N1) vaccine in an immunocompromised population: a prospective study comparing HIV-infected adults with HIV-uninfected adults.
abstract: BACKGROUND
  Limited data exist on the immunogenicity of the 2009 influenza A (H1N1) vaccine among immunocompromised persons, including those with human immunodeficiency virus (HIV) infection.
  
  
  METHODS
  We compared the immunogenicity and tolerability of a single dose of the monovalent 2009 influenza A (H1N1) vaccine (strain A/California/7/2009H1N1) between HIV-infected and HIV-uninfected adults 18-50 years of age. The primary end point was an antibody titer of ≥ 1:40 at day 28 after vaccination in those with a prevaccination level of ≤ 1:10, as measured by hemagglutination-inhibition assay. Geometric mean titers, influenza-like illnesses, and tolerability were also evaluated.
  
  
  RESULTS
  One hundred thirty-one participants were evaluated (65 HIV-infected and 66 HIV-uninfected patients), with a median age of 35 years (interquartile range, 27-42 years). HIV-infected persons had a median CD4 cell count of 581 cells/mm(3) (interquartile range, 476-814 cells/mm(3)) , and 82% were receiving antiretroviral medications. At baseline, 35 patients (27%) had antibody titers of >1:10. HIV-infected patients (29 [56%] of 52), compared with HIV-uninfected persons (35 [80%] of 44), were significantly less likely to develop an antibody response (odds ratio, .20; P = .003). Changes in the median geometric mean titer from baseline to day 28 were also significantly lower in HIV-infected patients than in HIV-uninfected persons (75 vs 153; P = .001). Five influenza-like illnesses occurred (2 cases in HIV-infected persons), but none was attributable to the 2009 influenza H1N1 virus. The vaccine was well tolerated in both groups.
  
  
  CONCLUSIONS
  Despite high CD4 cell counts and receipt of antiretroviral medications, HIV-infected adults generated significantly poorer antibody responses, compared with HIV-uninfected persons. Future studies evaluating a 2-dose series or more-immunogenic influenza A (H1N1) vaccines among HIV-infected adults are needed (ClinicalTrials.gov NCT00996970).
authors.affiliation: Infectious Disease Clinical Research Program, Uniformed Services University of Health Sciences, Bethesda, Maryland, USA. nancy.crum@med.navy.mil
authors.forename: Nancy F
authors.initials: NF
authors.lastname: Crum-Cianflone
authors.forename: Lynn E
authors.initials: LE
authors.lastname: Eberly
authors.forename: Chris
authors.initials: C
authors.lastname: Duplessis
authors.forename: Jason
authors.initials: J
authors.lastname: Maguire
authors.forename: Anuradha
authors.initials: A
authors.lastname: Ganesan
authors.forename: Dennis
authors.initials: D
authors.lastname: Faix
authors.forename: Gabriel
authors.initials: G
authors.lastname: Defang
authors.forename: Yun
authors.initials: Y
authors.lastname: Bai
authors.forename: Erik
authors.initials: E
authors.lastname: Iverson
authors.forename: Tahaniyat
authors.initials: T
authors.lastname: Lalani
authors.forename: Timothy
authors.initials: T
authors.lastname: Whitman
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Blair
authors.forename: Carolyn
authors.initials: C
authors.lastname: Brandt
authors.forename: Grace
authors.initials: G
authors.lastname: Macalino
authors.forename: Timothy
authors.initials: T
authors.lastname: Burgess
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use; D000914:Antibodies, Viral / Q000097:blood; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D016867:Immunocompromised Host; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000009:adverse effects / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D011446:Prospective Studies
chemical_list: D019380:Anti-HIV Agents; D000914:Antibodies, Viral; D007252:Influenza Vaccines