title: Immunogenicity and safety of ZOSTAVAX(®) approaching expiry potency in individuals aged ≥50 years.
abstract: BACKGROUND
  Age is a major risk factor for herpes zoster (HZ) and its potential long-term complication post-herpetic neuralgia (PHN). Due to the significant burden of HZ and PHN on patients' quality of life, it is vital that effective and well-tolerated vaccines are available to prevent HZ in older adults. ZOSTAVAX(®) vaccine was developed to prevent HZ and PHN in individuals ≥50 years (y) of age, and its clinical efficacy and safety have been demonstrated.
  
  
  OBJECTIVE
  This phase 4, open-label, multicenter study was undertaken to assess the immunogenicity and safety of a single dose of ZOSTAVAX (refrigerator-stable formulation) given within 6 mo of its expiry date in individuals ≥50 y of age. The geometric mean fold rise (GMFR) from pre-vaccination to 4 weeks post-vaccination in varicella zoster virus (VZV) antibody titers was calculated. An acceptable antibody response was defined as a lower 95% confidence interval (CI) of GMFR > 1.4. Solicited and unsolicited injection-site reactions and systemic adverse events were recorded.
  
  
  RESULTS
  The GMFR in VZV antibody titers was 3.1 (95% CI: 2.6, 3.8), satisfying the criterion for an acceptable VZV antibody response to ZOSTAVAX (minimum requirement: 1.4 GMFR). An acceptable rise in VZV antibody titers was observed in individuals of 50-59 y of age (GMFR 3.9; 95% CI: 2.9, 5.1) and in those ≥60 y of age (GMFR 2.5; 95% CI: 1.9, 3.2). ZOSTAVAX was well tolerated; no serious adverse events were reported.
  
  
  CONCLUSIONS
  ZOSTAVAX elicits an acceptable immune response in immunocompetent individuals ≥50 y of age when stored as directed and administered during the 6 mo prior to expiration.
authors.affiliation: ALTI Clinical Research Network, Angers, France.
authors.forename: Robert
authors.initials: R
authors.lastname: Arnou
authors.forename: Anne
authors.initials: A
authors.lastname: Fiquet
authors.forename: Stéphane
authors.initials: S
authors.lastname: Thomas
authors.forename: Christine
authors.initials: C
authors.lastname: Sadorge
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D004311:Double-Blind Method; D005260:Female; D006562:Herpes Zoster / Q000517:prevention & control*; D053061:Herpes Zoster Vaccine / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D051474:Neuralgia, Postherpetic / Q000517:prevention & control*
chemical_list: D000914:Antibodies, Viral; D053061:Herpes Zoster Vaccine