Seroprevalence of varicella-zoster virus in Korea.

Varicella-zoster virus (VZV) causes chickenpox and herpes zoster. Korea is assumed to have a high seroprevalence of VZV, although data are scant. A cross-sectional and age-stratified study was conducted to investigate the seroprevalence of VZV in different ages in the South Korean population. Four medical institutions were chosen in the southwestern area of Seoul in the vicinity of Gyeonggi-do. Serum samples were obtained at each institution from consenting patients during April-August, 2008. Anti-VZV IgG antibody was measured by an enzyme immunoassay. Of the 887 patients, 87.6% had anti-VZV IgG antibody. The prevalence of anti-VZV IgG antibody was 75% during the first 3 months after birth, but was only 13.6% 12 months after birth. Anti-VZV IgG antibody prevalence increased, first at 1-2 years of age, and then at 5-6 years of age. The seroprevalence rate exceeded 90% in subjects over 11 years of age. The results show that the seroprevalence of VZV is relatively high in the South Korean population. A study on the rate of varicella vaccination and the vaccine's efficacy in South Korea is warranted.

The clinical usefulness of the SD Bioline Influenza Antigen Test® for detecting the 2009 influenza A (H1N1) virus.

Though the 2009 worldwide influenza A (H1N1) pandemic has been declared to have ended, the influenza virus is expected to continue to circulate from some years as a seasonal influenza. A rapid antigen test (RAT) can aid in rapid diagnosis and allow for early antiviral treatment. We evaluated the clinical usefulness of RAT using SD Bioline Influenza Antigen Test® kit to detect the influenza virus, considering various factors. From August 1, 2009 to October 10, 2009, a total of 938 patients who visited the outpatient clinic at Korea University Guro Hospital with influenza-like illnesses were enrolled in the study. Throat or nasopharyngeal swab specimens were obtained from each of the patients. Using these specimens, we evaluated the influenza detection rate by rapid antigen test based on the real-time reverse-transcriptase polymerase chain reaction (rRT-PCR) method. In comparison with rRT-PCR, the sensitivity and specificity of the RAT were 44.0% and 99.9%, respectively. The cyclic threshold values of RAT negative specimens were higher than RAT positive specimens (30.1±3.1 vs. 28.3±3.9, p=0.031). The sensitivity of the RAT kit was higher in patients who visited clinics within two days of symptom onset (60.4% vs. 11.1%, p=0.026). The results of this study show that the RAT cannot be recommended for general use in all patients with influenza-like illness because of its low sensitivity. The RAT may be used, only in the settings with limited diagnostic resources, for patients who visit a clinic within two days of symptom onse.

Disease burden of herpes zoster in Korea.

BACKGROUND: The occurrence of herpes zoster can deteriorate the quality of life considerably, resulting in high disease burden. While Korea is assumed to have high disease burden of herpes zoster, there has been no researches analyzing this. OBJECTIVES: We performed this study to investigate the disease burden of herpes zoster in the Korean population as a whole. STUDY DESIGN: We used the database of the Health Insurance Review & Assessment Service of Korea and analyzed the data of patients who had herpes zoster as a principal diagnosis during the period from 2003 to 2007. We investigated the annual prevalence, rate of clinical visits, rate of hospitalization, and the pattern of medical services use. The socioeconomic burden of herpes zoster was calculated by a conversion into cost. RESULTS: Rates of clinic visits and hospitalizations due to herpes zoster during the 5-year period from 2003 to 2007 were 7.93-12.54 per 1000 population and 0.22-0.32 per 1000 population, respectively. Prevalence rates according to age increased sharply after 50 years and reached a peak at 70 years. The total socioeconomic cost of herpes zoster was $75.9-143.8 million per year, increasing every year by 14-20%. CONCLUSIONS: There is a heavy socioeconomic burden due to herpes zoster in Korea and indicate that appropriate policies need to be established to reduce this burden. Additional researches are also necessary to assess the safety, efficacy and cost-effectiveness of a herpes zoster vaccine in the Korean population.