title: Varicella-zoster virus immunity in dermatological patients on systemic immunosuppressant treatment.
abstract: BACKGROUND
  Primary varicella infection is caused by varicella-zoster virus (VZV). It is a common childhood infection, which is usually benign but can occasionally cause morbidity and mortality. In immunosuppressed adults, atypical presentation and disseminated disease can occur with significant morbidity and mortality. A VZV vaccine is available.
  
  
  OBJECTIVE
  This study was designed to measure the prevalence of immunity to VZV and to determine the predictive value of a self-reported history of varicella infection in a population of dermatological patients receiving systemic immunosuppressant therapy. We sought to assess the need for routine serological testing for varicella-zoster immunity in this cohort.
  
  
  METHODS
  Serological testing for VZV immunity was done on 228 patients receiving systemic immunosuppressive treatment for a dermatological condition. Information regarding a history of previous primary VZV infection was obtained from each patient.
  
  
  RESULTS
  Two hundred and twenty-eight patients had VZV serology performed. The mean age of the patients was 49·6 years. The prevalence of VZV seropositivity in this cohort was 98·7%. One hundred and two patients (44·7%) reported having a definite history of primary VZV. The sensitivity of a self-reported history of VZV infection was 45·3% with a specificity of 100%. The positive and negative predictive values of a self-reported history of VZV for serologically confirmed immunity were 100% and 2·3%, respectively.
  
  
  CONCLUSIONS
  The prevalence of VZV IgG antibodies in our cohort of Irish dermatology patients receiving immunosuppressive therapy is 98·7%. A recalled history of varicella infection is a good predictor of serological immunity. This study has shown that there are VZV-susceptible individuals within our cohort. These patients did not have a clear history of previous infection. We recommend serological testing of patients without a clear history of infection prior to the commencement of immunosuppressive therapy and vaccination of patients with negative serology.
authors.affiliation: Department of Dermatology, St Vincent's University Hospital, Elm Park, Dublin 4, Ireland. c.hackett@svuh.ie
authors.forename: C B
authors.initials: CB
authors.lastname: Hackett
authors.forename: D
authors.initials: D
authors.lastname: Wall
authors.forename: S F
authors.initials: SF
authors.lastname: Fitzgerald
authors.forename: S
authors.initials: S
authors.lastname: Rogers
authors.forename: B
authors.initials: B
authors.lastname: Kirby
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D002644:Chickenpox / Q000276:immunology*; D005260:Female; D014645:Herpesvirus 3, Human / Q000276:immunology*; D006801:Humans; D007110:Immunity, Active / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012871:Skin Diseases / Q000188:drug therapy* / Q000276:immunology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007166:Immunosuppressive Agents