Implementation of Adult Herpes Zoster Surveillance in West Philadelphia

Learning Objectives for this Presentation:
By the end of the presentation, participants will be able to describe the implementation of adult herpes zoster surveillance.

Background:
The Varicella Active Surveillance Project (VASP) expanded its surveillance network to better conduct active herpes zoster (HZ) surveillance among adults ≥50 years in West Philadelphia (WP). Baseline incidence data are needed to evaluate the HZ vaccine, which was licensed in May 2006 to prevent HZ among older adults.

Objectives:
To describe the implementation of active adult HZ surveillance in an urban setting.

Methods:
Surveillance sites in WP, including recently added nursing homes, internists, and dermatologists, reported HZ cases or absence of cases to VASP bi-monthly. Missing site reports were collected via telephone, fax, or in-person visit. HZ case reports among persons aged ≥50 years from WP received extensive investigation to obtain clinical information and confirm diagnosis. Cases reporting pain were re-contacted 4 months after their rash healed to assess post-herpetic neuralgia (PHN) occurrence.

Results:
During 2006, VASP received 154 confirmed adult (≥50 years) HZ cases. HZ rates increased with age from 1.7 cases per 1,000 population among 50-59 year olds to 2.9 and 2.8 cases per 1,000 population among those 70-79 years and ≥80 years, respectively. Emergency departments were the most common HZ reporting source (80, 52%). Among these adult HZ cases, 59% reported prior varicella histories, 34% had an uncertain history, and 7% had no history. One case received HZ vaccine 16 days prior to rash onset. Fifteen cases (10%) were hospitalized with no deaths. Eighty-eight percent received antiviral therapy. Most (128, 83%) experienced pain. Of 96 HZ cases who completed the PHN interview, 30 (31%) reported persistent pain.

Conclusions:
Baseline incidence data and ongoing surveillance of adult HZ in WP will be useful in evaluating the impact of the HZ vaccination program and also will broaden ongoing evaluations of the varicella vaccination program.