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Objective: To evaluate the safety and immunogenicity of revaccination with locally-produced Vi polysaccharide vaccine 3 years after the first dose in Chinese children aged 9 to 14 years. Methods: A randomized, placebo-controlled trial was conducted in Suzhou, Jiangsu, China. Six hundred and sixty-seven eligible children who had previously received a primary dose of Vi vaccine were randomly assigned to receive 1 dose of 30 μg Vi vaccine or placebo. In addition, 331 eligible children received 1 dose of Vi polysaccharide vaccine as a primary vaccination. Adverse events were followed for 28 days after vaccination. Serum samples were collected from a subgroup of participants on day 0 and day 28, and Vi antibodies were analyzed using a passive hemagglutination method. Results: Revaccination was found to be safe and immunogenic. No severe adverse events were observed. A significant increase in antibody titers after vaccination was observed among children who had and had not been previously vaccinated. Twenty-eight days after injection, the seropositive rate was 79% in both revaccination and primary injection groups; the geometric mean antibody titer was 1:40 in the primary injection group and 1:29 in the revaccination group (P = 0.24). Although the difference of attained geometric mean titers in follow-up sera was not significantly different in these 2 groups, the fold-rise of these titers from baseline was significantly higher in the primary injection group than in the revaccination group (7.7 versus 3.1, P < 0.001). Conclusion: We found that revaccination using the locally produced Vi polysaccharide vaccine among Chinese school-aged children was safe and increased antibody titers. Revaccination can be used to extend the duration of protection provided by Vi polysaccharide vaccine.

Objective. A hospital-based case-control study was conducted to identify characteristics of women at high risk of developing cervical cancer with special reference to sexual behavior in Korea. Methods. Histologically confirmed cases of invasive cervical cancer were selected from the Department of Gynecology, Seoul National University Hospital between September 1992 to May 1995 (n=203). Women with normal pap smear tests and women free of past history of any malignancies were regarded as controls (n=827). Information on risk factors were collected by both a self-administered questionnaire and a direct interview. Results. Uterine cervical cancer risk was higher in women with a less educated spouse (Ptrend=0.0003), women with a family history of cervical cancer (adjusted odds ratio [OR]=2.20., 95% confidence interval [CI] 1.21-4.01), women of shorter height (Ptrend=0.02), women with early age at first full term pregnancy (Ptrend=0.0005), and women who have had multiple full term pregnancies (Ptrend=0.006) by the multiple linear logistic analysis. Particularly noteworthy was a significant decreasing trend in the adjusted OR with the age at first sexual intercourse increasing (Ptrend=0.002) after adjusting the number of sexual partners. The husband's indecent sexual history showed a borderline significance (Ptrend=0.07). Conclusions. This study confirmed that the risk factors of cervical cancer in Korea are similar with those found in other countries. J Epidemiol, 1997; 7 :117-123.

Backgrounds/Aims: The purpose of this study was to evaluate the cost-effectiveness of 1 year and up to 5 years of antiviral treatment for chronic hepatitis B (CHB). Methods: Two ten-health-state Markov models were developed for CHB patients. The proportion of patients remaining alive in each health state, and healthcare costs and quality-adjusted life years (QALYs) were determined during annual cycles of these Markov models. The total healthcare costs, life years, and QALYs over the 40-year time horizon of the model were calculated. The perspectives of the cost-effectiveness analysis were the Korean healthcare system and the healthcare needs of the CHB patient. Results: Short-course therapy with α-interferon or 1-year treatment with pegylated interferon α-2a, lamivudine (LMV), or adefovir (ADV) had limited impact on disease progression. In contrast, either LMV-ADV or ADV-LMV as rescue medication administered for 5 years resulted in a more sustained decrease in the rate of disease progression. The cost-effectiveness threshold in Korea was estimated to be approximately 25,000,000 South Korean won. LMV administered for 1 year is cost-effective in comparison with no treatment for both HBeAg-positive and HBeAg-negative CHB patients, but longer duration antiviral therapies administered for up to 5 years in CHB patients were found to be highly cost-effective by international standards. Conclusions: Antiviral treatment of CHB with LMV or ADV for up to 5 years using the alternative antiviral agent as rescue medication appears to be a cost-effective strategy for both HBeAg-positive and HBeAg-negative CHB patients in Korea. Economic evaluation of antiviral therapies should be studied further and updated, particularly for newer agents. (Korean J Hepatol 2008;15: 25-41)

Interest in the use of economic evaluations in Korea as an aid for healthcare decision makers has been growing rapidly since the financial crisis of the Korean National Health Insurance fund and the separation in 2000 of the roles of prescribing and dispensing drugs. The Korean Health Insurance Review Agency (HIRA) is considering making it mandatory for pharmaceutical companies to submit the results of an economic evaluation when demanding reimbursement of new pharmaceuticals. The usefulness of the results of economic evaluations depends highly on the quality of the studies. The purpose of this paper, therefore, is to provide a critical review of economic evaluations of healthcare technologies published in the Korean context. Our results show that many studies did not meet international standards. Study designs were suboptimal, study perspectives and types were often stated incompletely, time periods were often too short, and outcome measures were often less than ideal. In addition, some articles did not distinguish between measurement and valuation of resource use. Capital, overhead and productivity costs were often omitted. Only half of the studies performed sensitivity analyses. In order to further rationalise resource allocation in the Korean healthcare sector, the quality of the information provided through economic evaluations needs to improve. Developing clear guidelines and educating and training researchers in performing economic evaluations is necessary.

To test the hypothesis that the intake of psychotropics may increase the risk of hip fracture, a cohort study was conducted upon elderly Korean women. The Korean Elderly Pharmacoepidemiology Cohort was constructed from members of the Korea Medical Insurance Corporation over 65 yr of age who were living in Busan Metropolitan City in 1993. Study participants (n=6,043) were female respondents to a self-administered question survey. Information on the intake of psychotropics was obtained from the drug prescription database, which contained all psychotropic prescriptions during any hospital admission over the two-year period between January 1, 1993 and December 31, 1994. The cohort follow-up has been conducted with information on hip fracture being collected from the Korea Medical Insurance Corporation medical treatment claims database over the four year period between January 1, 1993 and December 31, 1996. Three hundred and three subjects had received 745 psychotropics prescriptions and 56 cases of hip fracture were found. After adjusting for age, body mass index, and drinking history, it was found that the intake of psychotropics significantly increased the risk of hip fracture (adjusted odds ratio, 4.24; 95% confidence interval, 1.89-9.52). This study suggests that the intake of psychotropics might be an important risk factor for hip fracture in elderly Korean women.

Since the completeness of case ascertainment is directly related to the validity of a study, the evaluation of completeness is an essential feature of a cohort study. To estimate the completeness of cancer case ascertainment during a three year period (Jan. 1, 1993, to Dec. 31, 1995) in which the Seoul Male Cohort was followed up, we applied capture-recapture method. Data were obtained from the cancer registries, medical records and death certificates, with cases identified from each source numbering 103, 105, and 38, respectively. After eliminating duplicate cases, the total number was 141, and by using a log-linear model, the number of cases not detected by any of the three data sources was estimated to be 16. For all cancers, the estimated completeness of follow-up was 89.9%.