Disease burden and epidemiology of herpes zoster in pre-vaccine Taiwan

Herpes zoster, a common disease, has an important impact on the health of adults, particularly the elderly, and the health system. This study evaluated the disease burden and epidemiological characteristics of herpes zoster in Taiwan. Using herpes zoster-related ICD-9-CM codes used on Taiwan's National Health Insurance claims, we analyzed overall and age group differences in incidence, complications, utilization of healthcare facilities, lengths of stay, and cost of their medical care in Taiwan's population from 2000 to 2005. The overall annual incidence of zoster was 4.97 cases per 1000 people, with women having a significantly higher incidence than men (5.20 per 1000 vs. 4.72 per 1000, p<0.001). The incidence increased stepwise with age, with 5.18 cases per 1000 in people 40-50 years old, 8.36 in those 50-60, 11.09 in those 60-70, and 11.77 in those above 70 years old. The estimated lifetime risk of developing herpes zoster was 32.2%. Zoster-related hospitalizations and medical cost per patient increased with age. In conclusion, about two-thirds of Taiwan's zoster cases occur in adults older than 40 years old and about one-third of the population would develop zoster within their lifetime.