title: Impact of baseline covariates on the immunogenicity of a quadrivalent (types 6, 11, 16, and 18) human papillomavirus virus-like-particle vaccine.
abstract: BACKGROUND
  The quadrivalent (types 6, 11, 16, and 18) human papillomavirus (HPV) L1 virus-like-particle vaccine was 95%-100% effective in preventing cervical and genital disease related to HPV-6, -11, -16, and -18. Vaccine efficacy is thought to be mediated by humoral immunity. Here, we analyze the effect of the baseline characteristics of subjects on vaccine-induced immune responses.
  
  
  METHODS
  Immunogenicity data from 12,343 subjects 9-26 years old randomized to quadrivalent HPV vaccine or placebo in phase 2/3 studies were analyzed. Covariates examined were day 1 HPV serostatus, age, race/ethnicity, region of residence, lactation status, hormonal contraceptive usage, smoking status, Pap test diagnosis, immunosuppressant or anti-inflammatory agent use, and number of sex partners. Anti-HPV responses were summarized as serum anti-HPV-6, -11, -16, or -18 geometric mean titers 1 month after dose 3.
  
  
  RESULTS
  Age at vaccination initiation was inversely proportional to the vaccine-induced anti-HPV response. Vaccination of subpopulations of subjects who were seropositive at day 1 to a vaccine HPV type resulted in more robust anti-HPV responses to that type, compared with those in subjects who were seronegative at baseline. Anti-HPV responses were comparable among the remaining demographic subgroups.
  
  
  CONCLUSIONS
  The immunogenicity of quadrivalent HPV vaccine was comparable among subjects with differing baseline characteristics. These data support vaccination with quadrivalent HPV vaccine across a broad range of baseline subject characteristics.
authors.affiliation: H. Lee Moffitt Cancer Center, Tampa, FL 33612, USA. Anna.Giuliano@moffitt.org
authors.forename: Anna R
authors.initials: AR
authors.lastname: Giuliano
authors.forename: Eduardo
authors.initials: E
authors.lastname: Lazcano-Ponce
authors.forename: Luisa
authors.initials: L
authors.lastname: Villa
authors.forename: Terry
authors.initials: T
authors.lastname: Nolan
authors.forename: Colin
authors.initials: C
authors.lastname: Marchant
authors.forename: David
authors.initials: D
authors.lastname: Radley
authors.forename: Greg
authors.initials: G
authors.lastname: Golm
authors.forename: Kathleen
authors.initials: K
authors.lastname: McCarroll
authors.forename: Jimmy
authors.initials: J
authors.lastname: Yu
authors.forename: Mark T
authors.initials: MT
authors.lastname: Esser
authors.forename: Scott C
authors.initials: SC
authors.lastname: Vuocolo
authors.forename: Eliav
authors.initials: E
authors.lastname: Barr
mesh_terms: D000293:Adolescent; D000328:Adult; D052685:Alphapapillomavirus / Q000145:classification / Q000276:immunology*; D000917:Antibody Formation; D002648:Child; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D030361:Papillomavirus Infections / Q000276:immunology / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000276:immunology*; D015229:Sexually Transmitted Diseases, Viral / Q000276:immunology / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D053918:Papillomavirus Vaccines