Population-Based Study of the Epidemiology of Herpes Zoster in Korea

General epidemiological data regarding herpes zoster (HZ) are necessary for treatment and prevention of this disease. In addition, epidemiological data can play an important role in evaluating the efficacy and impact of vaccination. Though several epidemiological studies of HZ in Korea have been conducted, they usually depend on hospital-based data and may not be representative of HZ characteristics all over Korea. The purpose of this study was to evaluate the incidence and other epidemiological features of HZ in the general Korean population. We used population-based medical records from the Health Insurance Review & Assessment Service, which includes 50,908,646 medical insurance subscribers, to calculate the incidence of HZ. Also, we analyzed an age-stratified random sample of 1,375,842 individuals to study descriptive epidemiologic characteristics of HZ in Korea in 2011. We observed that the incidence of HZ was 10.4 per 1,000 person-years and was strongly correlated with age. Sex had a major influence on HZ incidence; overall, there were 12.6 cases per 1,000 person years in women and 8.3 cases per 1,000 person years in men. There was no difference in incidence according to the locality and season. Graphical Abstract Keywords: Herpes zoster, Epidemiology, Population-Based Study, Korea INTRODUCTION Herpes zoster (shingles, HZ) is caused by reactivation of the varicella-zoster virus (VZV). This virus can remain latent in neurons of cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia along the entire neuroaxis after primary infection with varicella (chickenpox), which usually occurs in childhood. It is characterized by a maculopapular or vesiculobullous rash along skin dermatomes, with severe pain (1). The most common complication of HZ is postherpetic neuralgia (PHN), or persistent pain lasting more than 3 months after the skin rash, even though the precise definition of PHN has not been defined yet. PHN can negatively affect quality of life, including physical, emotional, and social functioning, and may interfere with quality of life to a degree similar to congestive heart failure, depression, acute myocardial infarction, and diabetes (2). The live attenuated vaccine against HZ (Zostavax®) was recently introduced worldwide, and is recommended for people aged 50 yr or above with no contraindications. The efficacy of the vaccine in people over 60 yr old is 53% for the prevention of HZ and 65% for the prevention of PHN lasting 90 days or more (3). For people aged 50-59 yr old, the efficacy for HZ prevention is 70% (4). Despite the lack of population-based data, including the epidemiology of HZ in Korea, Zostavax® was approved in 2009 by the Ministry of Food and Drug Safety of Korea. General epidemiological data of HZ are necessary for the treatment and prevention of this disease. In addition, they can help to evaluate the efficacy and impact of vaccination. Though several epidemiological studies of HZ in Korea have been conducted, they usually depend on hospital-based data and may not be representative of HZ characteristics all over Korea (5, 6, 7). The purpose of this study was to evaluate the incidence and other epidemiological features of HZ in the general Korean population.