243. The clinical and laboratory diagnosis of herpes zoster: how good is it?
Session: Poster Abstract Session: Diagnostics: Virology
Thursday, October 27, 2016
Room: Poster Hall
Posters
  • Dooling_diagnosis of herpes zoster_IDWeek2016_Poster_243.pdf (1.6 MB)
  • Background: One in 3 people will develop Herpes Zoster (HZ) during their life. Differential diagnosis of a dermatomal vesicular rash include Herpes Simplex Virus (HSV), enteroviruses, contact dermatitis as well as HZ vaccine virus. Accurate clinical diagnosis of HZ may become more challenging with changes in epidemiology due to Varicella Zoster Virus (VZV) vaccination in children. This study aimed to evaluate the positive predictive value (PPV) of clinical diagnosis of HZ and examine laboratory performance of swab specimens.

     

    Methods: Between 2012-2015, as part of a prospective case control study in Kaiser Permanente Southern California, people ≥ 60 years old and diagnosed with HZ by their physicians, were contacted for enrollment. Study personnel obtained swabs of the rash and demographic data from consenting patients. All specimens were tested at the Centers for Disease Control for VZV via PCR (4 targets, open reading frame 22). Clinical HZ was lab confirmed if at least one specimen amplified 2 PCR targets. Patients who tested negative for VZV were tested for HSV.

    Results: 1,205 patients with incident HZ agreed to provide specimens. The median age of participants was 73 years, 64% were female and 51% were vaccinated. A median of 2 swabs per patient were collected. 1032 patients tested positive; a clinical PPV of 86%. The PPV was 81% for specimens collected day 0-2 following rash onset, 88% day 3-14 but dropped to 64% thereafter (X2=15, p<0.01). PPV did not vary significantly by age, sex, race or vaccination status. Among patients with ≥2 swabs, 1075 (92%) had concordant results and among lab confirmed HZ patients, 1975 swabs (95%) were positive. HSV1 and HSV2 were isolated from 7 and 8 patients, respectively, and 1 had a vaccine virus.

    Conclusion: Clinical diagnosis of HZ had a moderate PPV in this study and was highest between 3-14 days after rash onset. Lower PPV in the early and late stages of rash may reflect inaccurate clinical diagnosis or virus concentration below lab detection levels. Lab testing confirmed 16 infections other than wild type VZV. Swabs provide a reliable medium for PCR detection of VZV.

    Kathleen Dooling, MD, MPH1, Rafael Harpaz, MD, MPH2, Kay Radford, BS2, Kimberly Holmquist, MPHc3, D. Scott Schmid, PhD4, Yi Luo, MS3 and Hung Fu Tseng, Ph.D., MPH3, (1)DVD, Centers for Disease Control and Prevention, Atlanta, GA, (2)CDC, Atlanta, GA, (3)Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA, (4)Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA

    Disclosures:

    K. Dooling, None

    R. Harpaz, None

    K. Radford, None

    K. Holmquist, None

    D. S. Schmid, None

    Y. Luo, None

    H. F. Tseng, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.