title: Vitamin D levels and influenza vaccine immunogenicity among HIV-infected and HIV-uninfected adults.
abstract: Vaccination is the most important preventive strategy against influenza, however post-vaccination antibody responses are often inadequate especially among HIV-infected persons. Vitamin D deficiency has been suggested to adversely influence immune responses and is highly prevalent among HIV-infected adults. Therefore, we evaluated the association between 25-hydroxyvitamin D [25(OH)D] levels and post-influenza vaccination responses.
  
  
  
  We conducted a prospective cohort study evaluating the immunogenicity of monovalent influenza A (H1N1) vaccination among both HIV-infected and HIV-uninfected adults (18-50years of age) during the 2009-2010 influenza season. Antibody titers were evaluated at baseline, day 28, and 6months post-vaccination using hemagluttination inhibition assays. Serum 25(OH)D levels were measured at day 28. Univariate and multivariate regression analyses examined the association between 25(OH)D levels [categorized as <20ng/ml (deficiency) vs. ⩾20ng/ml] with the primary outcome of seroconversion. Secondary outcomes included seroprotection; a ⩾4-fold increase in titers; and geometric mean titers post-vaccination. Analyses were repeated using 25(OH)D levels as a continuous variable.
  
  
  
  A total of 128 adults [64 HIV-infected (median CD4 count 580cells/mm(3)) and 64 HIV-uninfected] were included. Seroconversion at day 28 post-vaccination was achieved in fewer HIV-infected participants compared with HIV-uninfected participants (56% vs. 74%, p=0.03). Vitamin D deficiency was more prevalent among HIV-infected persons vs. HIV-uninfected persons (25% vs. 17%), although not significantly different (p=0.39). There were no associations found between lower 25(OH)D levels and poorer antibody responses at day 28 or 6months for any of the study outcomes among either HIV-infected or HIV-uninfected adults.
  
  
  
  Vitamin D deficiency was common among both HIV-infected and HIV-uninfected adults, but lower levels did not predict antibody responses after H1N1 (2009) influenza vaccination. Low 25(OH)D levels do not explain poorer post-vaccination responses among HIV-infected persons.
authors: Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Scripps Mercy Hospital, San Diego, CA, United States; Naval Medical Center San Diego, San Diego, CA, United States. Electronic address: nancy32red@yahoo.com.
authors: Nancy F
authors: NF
authors: Crum-Cianflone
authors: Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States.
authors: Seunghyun
authors: S
authors: Won
authors: Operational Infectious Diseases, Naval Health Res. Ctr., San Diego, CA, United States.
authors: Rachel
authors: R
authors: Lee
authors: Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States; Naval Medical Center Portsmouth, Portsmouth, VA, United States.
authors: Tahaniyat
authors: T
authors: Lalani
authors: Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States; Walter Reed National Military Medical Center, Bethesda, MD, United States.
authors: Anuradha
authors: A
authors: Ganesan
authors: Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
authors: Timothy
authors: T
authors: Burgess
authors: Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States.
authors: Brian K
authors: BK
authors: Agan
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D000917:Antibody Formation; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D000071497:Immunogenicity, Vaccine; D007252:Influenza Vaccines / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: HIV-infected persons; Immunogenicity; Influenza vaccine; Vitamin D level