title: Unadjuvanted pandemic H1N1 influenza vaccine in HIV-1-infected adults.
abstract: We evaluated the immune response to a 2009 influenza A (H1N1) unadjuvanted vaccine in HIV-infected patients and assessed the boosting effect of a second dose. HIV-infected adults were enrolled and scheduled to receive the H1N1 unadjuvanted vaccine containing 15μg of A/California/7/2009 haemagglutinin. Anti-H1N1 antibody titers were measured at enrollment and 4-8 weeks after each vaccination by using haemagglutination inhibition (HI) and virus neutralization (NT) assays. One hundred and four patients were analyzed. Seroconversion, as measured by using HI and NT assays, was observed in 52 (50.0%) patients and 49 (47.1%) patients, respectively, after the first dose. Seroconversion rate evaluated by using NT, but not HI, antibody titers was associated with HIV RNA levels of <400copies/ml (odds ratio, 3.21; 95% CI, 1.15-8.96). Other parameters, including CD4 cell count, were not associated with seroconversion. In a cohort that received two vaccine doses at a 4-8-week interval (n=54), the seroconversion rate and geometric mean titer for HI antibodies were 44.4% (95% CI, 30.8-58.1%) and 30.5 (95% CI, 19.9-46.9) after the first dose, respectively, and 48.1% (95% CI, 34.4-61.9%) and 39.0 (95% CI, 26.1-58.2) after the second dose, respectively. Among HIV-infected patients, the seroconversion rate was around 50% after the first dose of unadjuvanted vaccine. A second dose of vaccine had a limited boosting effect on immunity in this patient cohort.
authors: Department of Infectious Diseases, Graduate School of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. shatake-tky@umin.ac.jp
authors: Shuji
authors: S
authors: Hatakeyama
authors: Kiyoko
authors: K
authors: Iwatsuki-Horimoto
authors: Koh
authors: K
authors: Okamoto
authors: Yoko
authors: Y
authors: Nukui
authors: Nahoko
authors: N
authors: Yata
authors: Akira
authors: A
authors: Fujita
authors: Shigeki
authors: S
authors: Inaba
authors: Hiroshi
authors: H
authors: Yotsuyanagi
authors: Yoshihiro
authors: Y
authors: Kawaoka
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D000917:Antibody Formation; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000276:immunology* / Q000821:virology; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology; D006801:Humans; D007117:Immunization, Secondary; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009500:Neutralization Tests; D012367:RNA, Viral / Q000097:blood
chemical_list: D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D012367:RNA, Viral