1 Descriptive Epidemiology of Adult Herpes Zoster and Post-herpetic Neuralgia from an Active Surveillance Project, Antelope Valley, California, Christina L. Jackson, MPH Research Analyst II Varicella Active Surveillance Project Acute Communicable Disease Control Los Angeles Department of Public Health

2 Background: Herpes zoster (HZ) Reactivated varicella zoster virus (VZV) Localized, painful cutaneous eruption Most frequently seen in older adults and immuno-compromised individuals Approximately 30% of adults will experience HZ in lifetime In US, estimated 1 million HZ episodes annually Photo Source: Wikipedia/GNUFDL

3 Background (2) Herpes zoster vaccine (Zostavax) –Recommended for all persons ≥ 60 years for prevention of HZ –Approved by Food and Drug Administration in May of 2006 –Endorsed by Advisory Committee on Immunization Practices in October of 2006

4 Antelope Valley Los Angeles County Northern Los Angeles County, borders Southeastern Kern County 72 miles from downtown Los Angeles ~ 2,200 square miles with total population ~ 350,000 Palmdale and Lancaster two main cities Edwards Air Force Base Part of AV Varicella Active Surveillance Project

5 Presentation Objectives Describe the incidence of herpes zoster (HZ) in adults ≥ 50 years from January 1, 2006 to December 31, 2007 Describe clinical presentation of adult HZ Describe HZ cases that reported post- herpetic neuralgia (PHN) upon follow-up interview Describe physician prescribing practices Discuss HZ vaccine policy implications

6 Methods: Case Definitions Verified HZ Case –Unilateral vesicular rash in a dermatomal distribution with acute rash onset –Diagnosed by a licensed health care provider HZ complication –Verified HZ case with secondary condition diagnosed by health care provider Post-herpetic neuralgia (PHN) –Persisting pain or discomfort lasting ≥ 90 days after rash onset

7 Methods: Surveillance Sites Surveillance sites (N~90) include the following: –Health maintenance organizations, private medical providers, emergency rooms and hospitals, community-based clinics, skilled nursing facilities Two week reporting periods –Active surveillance –Provide basic demographic information for contact purposes

8 Methods: Interview Procedures (1) Completion of standardized case report by scripted telephone interview with case or caretaker –Demographics –Clinical presentation –Pain assessment Onset of pain Presence at time of interview Intensity of pain: rated on a scale 0-10 Duration of pain –Medical Complications- such as bacterial super-infection –Prescription medication

9 Methods: Interview Procedures (2) Medical chart review –Used for diagnosis verification or if case/caretaker not available for interview –Verification of HZ complications PHN follow-up –Done at 4 months after HZ rash onset only for those reporting pain at initial interview

10 Methods: Data Analysis US census estimates- for age/race- ethnicity specific denominators Data analyzed with SAS 9.2 Statistical test: Chi-squared Statistical significance: p < 0.05

11 Results: Verified HZ Case Reports Antelope Valley, California, Total Cases Reported 2006: 425 Total 2007: 555 Total 316 Verified 109 Excluded 403 Verified 152 Excluded

12 Results: HZ Incidence by Age Antelope Valley, California, **Incidence per 1,000 **Rates based on Census Estimates for Adults age 50 and older

13 Results: HZ Incidence by Age and Sex Antelope Valley, California, **Incidence per 1,000 **Rates based on Census Estimates for Adults age 50 and older Statistically significant difference between sex p<0.05

14 Results: HZ Incidence by Race-Ethnicity Antelope Valley, California, *Incidence per 1,000 *Rates based on Census Estimates for Adults age 50 and older Year Race/Ethnicity# Cases (Incidence*) Caucasian/Non- Hispanic 188 (3.4)215 (3.9)403 (3.6) African American 24 (3.0)36 (4.2)60 (3.6) Hispanic64 (4.2)76 (4.6)140 (4.4) API/American Indian 13 (2.7)11 (2.2)24 (2.5) Other/Unknown27 (-)65 (-)92 (-)

15 Results: Clinical Description Antelope Valley, California, Dermatome –Cervical: 213 (29.6 %) –Thoracic: 371 (51.6%) –Lumbar-sacral: 117 (16.3%) –Unknown: 18 (2.5%) Rash Extent –<1 square inch: 95 (13.2%) –1-4 square inches: 242 (33.7%) –5-10 square inches: 145 (20.2%) –>10 square inches: 141 (19.6%) –Unknown: 96 (13.3%) Complications (29) –Bacterial Superinfection: 19 –Ocular Complication: 5 –Segmental Paralysis: 1 –Cutaneous Dissemination: 4 Hospitalizations (6) –Immunocompromised: 1 –Bacterial superinfection: 1 –HZ opthalmicus: 1 –HZ encephalitis: 3

16 Results: Severity of Pain Antelope Valley, California,

17 Results: Pain and PHN by Age Group Antelope Valley, California, Pain at initial interview –30 days after case reported –Yes: 174 cases (27.5%) –No: 360 cases (57.0%) –Unable to obtain: 98 cases (15.5%) Reporting pain at ≥90 days after rash onset –Yes: : 44 cases (33.8%) 60-69: 34 cases (26.2%) 70-79: 52 cases (40.0%) –Pain affect daily activities: 70 # cases reporting yes to pain at follow up interview by age group

18 Results: Antiviral Usage Antelope Valley, California, Age Group n (%) n (%) 70+ n (%) Total n (%) Antiviral 228 (31.7)176 (24.5)211 (29.3)615 (85.5) n=228n=176n=211n=615 ≤ 72 hrs 128 (56.1)106 (60.2)148 (70.1)382 (62) ≥ 72 hrs 100 (43.9)70 (39.8)63 (29.9)233 (38) p-value >0.05<0.05

19 Results: Pain Medication Use Antelope Valley, California, Age (yrs)50-59 n= n= n=256 Total n=719 Pain Meds. n (%) Anticonvulsant 19 (7.3)22 (10.6)37 (14.5)78 (10.9) Antidepressant 17 (6.5)9 (4.5)15 (5.9)41 (5.7) Steroid 46 (17.6)29 (14.4)25 (9.8)100 (13.9) Opioid 103 (39.3)89 (44.3)101 (39.5)293 (40.8) Topical 25 (9.5)29 (14.4)46 (18.0)100 (13.9) Non-prescription 70 (26.7)53 (26.4)53 (20.7)176 (24.5) Significant increase by age group Significant decrease by age group

20 Conclusions HZ Incidence rates increased with advancing age and between sex Large majority of HZ cases reported severe pain Use of medication varied with advancing age –antiviral treatment –prescription and non-prescription pain medication

21 Conclusions: PHN & Vaccine Policy Implications Proportion of HZ cases reporting PHN did not significantly vary with advancing age (p=0.15) –27.0 % of cases reported PHN in the year age group –21.0% of cases reported PHN in the year age group –35.1% of cases reported PHN in the 70+ year age group The proportion of PHN reported in persons years was comparable to older age groups suggests potential for Zostavax

22 Limitations Limited laboratory confirmation of HZ Need to evaluate current HZ surveillance system –Possible under-reporting of HZ –VASP incidence HZ rates one third less than administrative data sources –Surveillance system designed for varicella reporting –Current efforts to evaluate reporting system

23 Acknowledgements: Rachel Civen, MD, MPH Laurene Mascola, MD, MPH Stephanie Bialek, MD, MPH Adriana Lopez, MHS Antelope Valley VASP Staff: Karen Kuguru Michael Borquez Michelle Armijo Amanuel Hussien