Seroepidemiology of HBV infection in South Korea, 1995 through 1999

Prevention of Hepatitis B Virus Infection and Liver Cancer

Hepatocellular carcinoma (HCC) is one of the five leading causes of cancer death in human. Hepatitis B virus (HBV) is the most common etiologic agent of HCC in the world. Prevention is the best way to control cancer. There are three levels of liver cancer prevention, i.e., primary prevention by HBV vaccination targeting the general population starting from birth dose, secondary prevention by antiviral agent for high-risk subjects with chronic HBV infection, and tertiary prevention by antiviral agent to prevent recurrence for patients who have been successfully treated for liver cancer. Primary prevention by hepatitis B vaccination is most cost effective, the cancer preventive efficacy support it as the first successful example of cancer preventive vaccine in human. Addition of hepatitis B immunoglobulin immediately after birth and antiviral agent during the third trimester of pregnancy to block mother-to-infant transmission of HBV are existing or possible emerging strategies to enhance the prevention efficacy of HBV infection and its related liver cancer. Secondary prevention with current antiviral agents may reduce the risk or delay the onset of HCC development, but could not eradicate HBV infection and HCC. Better antiviral therapeutic agents are needed for better secondary prevention.

Negative Association of Hepatitis B Virus With Hearing Impairment

PURPOSE

Hearing impairment is one of the most common chronic diseases causing deterioration of the quality of life in elderly individuals. Several viral infections have been suggested to cause hearing impairment. We investigated association of hepatitis B virus (HBV) infection with hearing impairment using a representative sample of the Korean population.

METHOD

Participants included 6,583 men and 8,702 women, who were ≥ 20 years of age from the Korea National Health and Nutritional Examination Surveys of the Korean population (2010-2012). Air-conduction pure-tone thresholds were measured in a soundproof booth using an automatic audiometer for each ear at 6 frequencies (500, 1000, 2000, 3000, 4000, and 6000 Hz). An audiometric test and a laboratory examination, including an HBV surface antigen (HBsAg) test, were performed.

RESULTS

Subjects who are HBsAg positive had lower average of pure-tone thresholds and lower prevalence of hearing impairment at both low/mid and high frequency compared with those without. Adjusted means of hearing thresholds were also lower among subjects who are HBsAg positive compared with subjects who are HBsAg negative. After the adjustment for age and gender, the odds of high-frequency mild hearing impairment were lower for subjects with HBV infection. In the multiple logistic regression analyses adjusting for confounding variables, the significant negative association between HBV infection and high-frequency mild hearing impairment still remained.

CONCLUSIONS

Contrary to previous reports, subjects who are HBsAg positive had a lower prevalence of hearing impairment compared with subjects who are HBsAg negative. Further studies are warranted to investigate the underlying mechanism regarding their negative relationship.

Real-world single-center experience with entecavir and tenofovir disoproxil fumarate in treatment-naïve and experienced patients with chronic hepatitis B

BACKGROUND/AIM

The goal of antiviral therapy for chronic hepatitis B (CHB) is to improve survival of the patients by achieving a complete virological response (CVR). This study aimed to evaluate long-term efficacy of entecavir (ETV) and tenofovir disoproxil fumarate (TDF) in nucleos(t)ide analog (NA)-naïve and NA-experienced Korean patients with CHB and to determine the incidence of cirrhosis-related complications in these patients.

PATIENTS AND METHODS

We retrospectively reviewed medical records of all patients treated with ETV or TDF from July 2007 to January 2017. We examined CVR and analyzed the predictive factors influencing the rate of CVR and evaluated the incidences of cirrhosis-related complications.

RESULTS

The proportion of patients who achieved CVR was 94.2% in the ETV group and 91.1% in the TDF group (P = 0.358). Among patients who achieved CVR, the mean time to CVR was 13.5 ± 14.3 months in the ETV group and 11.5 ± 10.6 months in the TDF group (P = 0.169). Positive predictive factors for CVR included the current treatment with TDF, a low hepatitis B virus DNA level, negative hepatitis B e-antigen status, and high alanine aminotransferase level in baseline laboratory test. The annual incidence rate of HCC was 127 per 10,000 patient-years (1.27% per year) in ETV group, and 85 per 10,000 patient-years (0.85% per year) in TDF group (P = 0.526).

CONCLUSION

Both ETV and TDF therapy resulted in a high CVR, and the annual incidence rates of HCC and other cirrhosis-related complications were not significantly different between the two treatment groups.

Association of HLA-DP variants with the responsiveness to Hepatitis B virus vaccination in Korean Infants

Recently, HLA-DP single nucleotide polymorphisms (SNPs) have been reported to be related to responsiveness to hepatitis B virus (HBV) vaccination. The aim of this study was to investigate associations between HLA-DP SNPs and responsiveness to HBV vaccine in Korean infants. A total of 290 healthy Korean infants who were registered to Seoul Metropolitan Public Cord Blood Bank during the period of February 2007 to December 2011 were enrolled. Anti-HBs antibody level was analyzed after three doses of HBV vaccination. Genotyping of HLA-DPA1 SNPs (rs3077 and rs3830066) and HLA-DPB1 SNPs (rs7770370, rs7770501, rs3128961, and rs9277535) were performed by PCR-sequencing. HLA-A, -B, and -DRB1 genotyping was also performed by PCR-sequence-specific oligonucleotide probe kits. HLA-DPB1 SNPs (rs7770370, rs7770501, rs3128961, and rs9277535) were associated with HBV vaccine response. Allele frequencies of rs7770370 A, rs7770501 C, rs3128961 G, and rs9277535 A were significantly higher in responders than in non-responders (all p<0.01). Anti-HBs antibody levels were different according to genotypes of DPB1 rs7770370, rs7770501, rs3128961, and rs9277535 (all p<0.01). In multivariate analysis, HLA-DPB1 rs7770370 AA genotype was significantly associated with HBV vaccine response (relative risk, RR=2.5, p=0.033) and high-titer vaccine response (RR=2.7, p<0.001). In conclusion, HLA-DPB1 SNPs were significantly associated with responses to HBV vaccination in Korean infants.

Association of HLA alleles with the responsiveness to hepatitis B virus vaccination in Korean infants

Hepatitis B virus (HBV) vaccination is the most effective means of countering HBV-related morbidity and mortality, and individuals who do not respond to vaccination (non-responders) are problematic. The aim of the present study was to investigate associations between HLA and responsiveness to HBV vaccine in Korean infants. A total of 944 healthy Korean infants 9-12 months old were enrolled, and HLA distribution was compared among subgroups in accordance with the response to HBV vaccination. The HLA distribution of the subjects was similar to known Korean population data and did not deviate from the HWE proportions. The alleles that showed positive associations with non-responsiveness (<10mIU/mL) or low antibody titer (<100mIU/mL) were HLA-A*33, B62, DRB1*04, and DRB1*07, while the alleles A*02 and DRB1*08 showed negative associations. Among these alleles, B62, DRB1*07 and DRB1*08(-) showed significant associations with a poor or decreased response to vaccination even after correction (OR=1.83, 1.99, 5.63; pc<0.05) and also showed dose effects. After stratification by other associated alleles at different loci, B62 and DRB1*07 were independently associated with non-responsiveness, but A*02(-) and DRB1*08(-) lost their individual associations. The combined association of A*02(-)-DRB1*08(-) and B62-DRB1*08(-) was significant (OR=25.2 and 24.5; pc<0.05). Although the hierarchy is not clear, we can assume the following: (i) B62 and DRB1*07 have independent effects, (ii) DRB1*08(-) has a very strong and synergic effect, and (iii) there is probability of a third factor controlling A*02(-) and DRB1*08(-) with an effect on non-responsiveness to HBV vaccination in Korean infants.

Prevention of hepatitis B virus infection and liver cancer

Hepatocellular carcinoma (HCC) is one of the five leading causes of cancer death in human. Hepatitis B virus (HBV) is the most common etiologic agent of HCC in the world, particularly in areas prevalent for HBV infection such as Asia, Africa, southern part of Eastern and Central Europe, and the Middle East. Risk factors of HBV-related HCC include (1) viral factors-persistent high viral replication, HBV genotype C or D, pre-S2 or core promoter mutants; (2) host factors-older age (>40 years old) at HBeAg seroconversion, male gender; (3) mother-to-infant transmission; and (4) other carcinogenic factors-smoking, habitual use of alcohol, etc. Prevention is the best way to control cancer. There are three levels of liver cancer prevention, i.e., primary prevention by HBV vaccination targeting the general population, secondary prevention by antiviral agent for high-risk subjects with chronic HBV infection, and tertiary prevention by antiviral agent to prevent recurrence for patients who have been successfully treated for liver cancer. Primary prevention by hepatitis B vaccination is most cost effective. Its cancer preventive efficacy supports it as the first successful example of cancer preventive vaccine in human. This experience can be extended to the development of other cancer preventive vaccine. Careful basic and clinical research is needed to develop ideal vaccines to induce adequate protection. Understanding the main transmission route and age at primary infection may help to set the optimal target age to start a new cancer preventive vaccination program. Besides timely HBV vaccination, the earlier administration of hepatitis B immunoglobulin immediately after birth, and even antiviral agent during the third trimester of pregnancy to block mother-to-infant transmission of HBV are possible strategies to enhance the prevention efficacy of HBV infection and its related liver cancer.

Transmission of hepatitis C virus by occupational percutaneous injuries in South Korea

Korea is an endemic area of hepatitis. Hepatitis C virus (HCV) infections caused by occupational percutaneous injuries are a serious problem for healthcare workers and there has been a gradual increase in the number of HCV infections. We therefore determined the transmission rate of HCV after occupational percutaneous injury. This was a retrospective cohort study reviewing all occupational blood exposure reports made between January 1, 2004, and December 31, 2008, at a university-affiliated acute care hospital. Over the 5-year study period, there were 1,516 accidents of occupational exposure to blood; of these, 327 (21.6%) were to the blood of HCV-infected patients and 3 (0.9%) healthcare workers became infected with HCV (95% CI 0.6-8.8). In Korea, although the bloodborne accidents leading to exposure to HCV occurred frequently (21.6%), the transmission rate was very low (0.92%).

Hepatitis B virus and cancer prevention

Prevention of chronic hepatitis B virus (HBV) infection can successfully reduce the incidence of liver cancer. It is the first example of cancer-preventive vaccine in human, which proves that prevention of the infection of an infectious agent can prevent its related cancer.Chronic HBV infection can lead to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). HCC is one of the five major cancers in the world population. Hepatitis B virus (HBV) is the most important etiologic agent of liver cancer globally, particularly in high-prevalence areas of liver cancer.The world's first universal HBV vaccination program was launched in Taiwan in July 1984. It has provided evidences that the prevalence of HBV infection has been reduced remarkably to approximately one-tenth of the original prevalence. Furthermore, reduction of the HCC incidence in children aged 6-14 years have been demonstrated in the vaccinated birth cohorts. Recently, we have further provided evidence that the prevention of HCC by this HBV vaccine extends from childhood to early adulthood.The risk of developing HCC for vaccinated cohorts was associated with incomplete HBV vaccination; prenatal maternal hepatitis B surface antigen (HBsAg) seropositivity; and prenatal maternal HBeAg seropositivity. Failure to prevent HCC results mostly from unsuccessful control of HBV infection by highly infectious mothers. Future strategies to increase the global coverage rate of HBV immunization and to interrupt mother-to- infant transmission may enhance the cancer prevention effect of HBV immunization.

Quantitative measurement of serum hepatitis B surface antigen using an immunoradiometric assay in chronic hepatitis B

PURPOSE

Measurement of serum hepatitis B virus surface antigen (HBsAg) levels is important for the management of chronic hepatitis B patients in terms of monitoring response to antiviral therapy. This study aimed to evaluate the diagnostic performance of a new diagnostic kit, which quantitatively measures serum HBsAg level using an immunoradiometric assay (IRMA)-based method. Measurements were compared with those obtained using a chemiluminescent microparticle immunoassay (CMIA)-based method.

METHODS

The blood samples of 96 patients with chronic hepatitis B were used in this study. Copy numbers of serum hepatitis B virus (HBV) DNA were determined in 23 of these samples. The correlation between and the concordance of IRMA and CMIA results were determined using Pearson's correlation coefficients. P values of 0.05 were considered to be statistically significant throughout.

RESULTS

Laboratory diagnoses based on IRMA were wholly in agreement with those based on CMIA. Furthermore, serum HBsAg levels by IRMA were found to be highly correlated with those determined by CMIA (correlation coefficient R (2) = 0.838, p < 0.001). Serum HBsAg level and serum HBV DNA copies were found to be linearly related by both methods (R (2) = 0.067, p = 0.316 by IRMA, and R (2) = 0.101, p = 0.215 by CMIA).

CONCLUSION

The diagnostic performance of the investigated IRMA method of determining HBsAg levels was found to be comparable with that of a CMIA-based method in chronic hepatitis B patients.

Hepatitis B vaccination: disease and cancer prevention-a Taiwanese experience

Prevention is most cost effective toward successful control of hepatitis B virus (HBV) infection and its complications. It is particularly urgent where HBV infection and hepatocellular carcinoma (HCC) are prevalent. To achieve better results of primary HCC prevention globally, higher world coverage rates of HBV vaccine, better strategies against breakthrough infection/nonresponder, and good long-term protection are needed. With the universal hepatitis B vaccination program starting from neonates in most countries, HBV infection and its complications will be further reduced in this century. An effective decline in the incidence of HCC in adults is expected in the near future. The concept of a cancer preventive vaccine, using HBV as an example, can be applied further to other infectious agents and their related cancers.

Current status of liver diseases in Korea: hepatitis B

Hepatitis B virus (HBV) infection is the one of the most common causes of the liver diseases in Korea. Since the discovery of Australia antigen (hepatitis associated antigen, or HBsAg later), hepatitis associated antigen was tested widely. HBsAg was detected in 6.6-8.6% in 1980's. Later, it decreased to 5.7% in 1990's. Remarkably, seropositivity of the children deceased to 0.2% after the nationwide vaccination program. Although hepatitis B vaccines are highly effective, the failure rate of perinatal prophylaxis in babies born to HBsAg positive mother was reported to be 4.25%. Treatment of chronic hepatitis B was initiated after the introduction of interferon alpha. Lamivudine opened a new era of oral antiviral agent, and it has been widely used in Korea since 1999. Adefovir was proven to have a good efficacy for lamivudine-resistant chronic hepatitis B. Newer potent antiviral agents such as entecavir, clevudine, and telbivudine are available currently. Further studies are warranted for understanding factors influencing natural history, improving treatment outcomes, and overcoming vaccine non-response.

Understanding the rapid increase in life expectancy in South Korea

OBJECTIVES

We assessed life expectancy increases in the past several decades in South Korea by age and specific causes of death.

METHODS

We applied Arriaga's decomposition method to life table data (1970-2005) and mortality statistics (1983-2005) to estimate age- and cause-specific contributions to changes in life expectancy.

RESULTS

Reductions in infant mortality made the largest age-group contribution to the life expectancy increase. Reductions in cardiovascular diseases (particularly stroke and hypertensive diseases) contributed most to longer life expectancy between 1983 and 2005 (30% in males and 28% in females). Lower rates of stomach cancer, liver disease, tuberculosis, and external-cause mortality accounted for 30% of the male and 20% of the female increase in longevity. However, higher mortality from ischemic heart disease, lung and bronchial cancer, colorectal cancer, breast cancer, diabetes, and suicide offset gains by 10% in both genders.

CONCLUSIONS

Rapid increases in life expectancy in South Korea were mostly achieved by reductions in infant mortality and in diseases related to infections and blood pressure.

Hepatitis B vaccinations among Koreans: Results from 2005 Korea National Cancer Screening Survey

Background

Liver cancer is one of most commonly diagnosed cancers among Koreans. Chronic hepatitis B virus (HBV) infection is a major risk factor for liver cancer. HBV infection can be prevented by effective screening and vaccination programs. The purpose of this study is to examine the status of HBV infection and the predictors associated with HBV vaccination.

Methods

The study population was derived from the 2005 Korea National Cancer Screening Survey (KNCSS). The KNCSS is an annual cross-sectional survey that uses a nationally-representative random sampling to investigate cancer screening rates. A total of 1,786 Koreans over 40 years of age participated in this study.

Results

Of all the participants, 5.9% reported HBV positive (HBsAg+, HBsAb-), 41.8% were HBV negative but protected (HBsAg-, HBsAb+), and 52.3% were unprotected (HBsAg-, HBsAb-). Among unprotected individuals (n = 934), 23.1% reported to have received the vaccination. About half of those who had vaccinations completed the 3-shot vaccine series. In multiple analyses, education, having private cancer insurance, alcohol use, having regular check-up, and doing regular exercise were associated with completed HBV vaccination.

Conclusion

This study result suggests that we need a liver cancer education program to increase HBV awareness and to increase the liver cancer prevention message among low educated populations.

[Recent etiology and clinical features of acute viral hepatitis in a single center of Korea]

BACKGROUND AND AIMS

The etiology of acute viral hepatitis in Korea has been dynamically changing during the recent years. The aim of this study was to investigate the recent etiology and the clinical features of acute viral hepatitis in a single center of Korea.

METHODS

We performed a retrospective analysis of a prospective cohort of 55 patients who were diagnosed with acute viral hepatitis A to E during the period from May 2005 to August 2006. In addition to the clinically acute manifestations, the confirmatory serological tests were performed for the diagnosis of acute hepatitis A, B, C and E.

RESULTS

The proportion of patients with acute viral hepatitis A, B, C, E and others were 56.4% (n=31), 12.7% (n=7), 18.2% (n=10), 9.1% (n=5) and 3.6% (n=2), respectively. The mean age of the patients with acute hepatitis A, B, C and E were 29.1+/-4.38, 38.7+/-11.72, 45.3+/-17.62 and 32.4+/-6.58 years, respectively. There was no fatal case. All cases of acute hepatitis B and six out of ten cases of acute hepatitis C recovered spontaneously. Four out of the five patients with acute hepatitis E had no history of travel to endemic area.

CONCLUSIONS

The most common etiology of acute viral hepatitis in Korea is hepatitis A virus, and hepatitis C and B virus were the next most common causes. The sporadic cases of acute hepatitis E were not rare, and coinfection of HAV and HEV was observed. A multicenter, prospective study is warranted in the future.

Estimated prevalence and risk factor for age-related maculopathy

PURPOSE

To assess the estimate prevalence and risk factors for age-related maculopathy (ARM) in Seoul, Korea.

PATIENTS AND METHODS

We examined 9,530 subjects with, 40 years of age or older between January 2006 and December 2006 in Seoul, Korea. Subjects underwent fundus photography, clinical examinations (including blood analyses), and completed detailed questionnaires. Fundus images were graded according to definitions from the Wisconsin Age-Related Maculopathy Grading System.

RESULTS

ARM was present in 235 subjects, corresponding to an estimate prevalence of 2.46%. Hepatitis B infection (positive status for HBsAg and HBcAb), serum triglyceride levels and high density lipoprotein levels remained as significant risk factors after age-adjustment. Multivariate analyses showed that the prevalence of ARM was significantly higher in older subjects [odds ratio (OR) 1.134; 95% CI 1.114-1.154] and those who were seropositive for hepatitis B surface antigen (OR 2.566; 95% CI 1.519-4.335).

CONCLUSION

The estimated prevalence of ARM was 2.46%. Age and hepatitis B infection may increase the risk of ARM.

Liver cancer in Korea

Hepatocellular carcinoma (HCC) is a highly malignant cancer and third major cause of death in Korean. It is more prevalent among men in the sixth to seventh decades. HCC is particularly prevalent in Korea where the age-standardized incidence rate is 45.0/100 000 population in males and 12.0/100 000 population in females. The death rate from HCC is 20.0/100 000 population. Approximately 65-75% of HCC patients were positive for hepatitis B surface antigen (HBsAg), where 10-20% of patients were anti-hepatitis C virus (HCV) positive. The high incidence rate of HCC in Korea is thought to be related to the high carrier rate of hepatitis B virus (HBV) in the general population. For primary prevention, a nationwide HBV vaccination program has been conducted since the late1980s in Korea. Although advances have been made in the various methods of management of HCC, there has been little overall survival improvement during the past 20 years. Only few patients are candidates for potentially curative forms of treatment. Therefore, the early detection of HCC is a key issue. When compared with clinical outcomes of HCC based on recent 10-year institutional data, our screening and surveillance programs might enable early detection and increased applicability of curative treatments.

Long-term outcome of chronic hepatitis B based on histological grade and stage

BACKGROUND AND AIM

This study evaluated the long-term outcome and prognostic factors of chronic hepatitis B, based on histological grade and stage.

METHODS

A total of 188 patients with chronic hepatitis B were followed for a mean 119.8 months. Ultrasonography and clinical assessment were performed regularly. In addition, liver biopsy specimens were re-evaluated based on histological grade and stage.

RESULTS

During follow-up, cirrhosis developed in 62 patients, decompensation in 20 patients, and hepatocellular carcinoma (HCC) in 21 patients. The serum alanine aminotransferase (ALT) level at the time of liver biopsy was significantly correlated with the grades of lobular and porto-periportal activity. The development of cirrhosis correlated well with the grade of porto-periportal activity and stage of fibrosis. The probabilities of developing cirrhosis, decompensation and HCC were significantly higher in patients whose ALT levels were persistently elevated without flares or flared-up without normalization than in patients whose ALT levels flared-up then normalized or were normally sustained. By multivariate analysis, age and biochemical profile during follow-up were independent prognostic factors for chronic hepatitis B.

CONCLUSIONS

The results demonstrate that histological grade and stage, and biochemical profile during follow-up in patients with chronic hepatitis B are important prognostic factors. Therefore, effective control of hepatitis activity might improve the long-term outcome of chronic hepatitis B patients.

Impact of economic crisis on cause-specific mortality in South Korea

BACKGROUND

Economic changes can be powerful determinants of health. In the late 1990s, South Korea experienced a steep economic decline. This study examines whether the massive economic changes affected trends in all-cause and cause-specific mortality in South Korea.

METHOD

Mid-year population estimates of 5 year age groups (denominators) and death certificate data (numerators) from the National Statistical Office of Korea were used to compute cause-specific age-standardized mortality rates before and after the economic crisis.

RESULTS

All-cause mortality continued to decrease in both sexes and all age groups during the crisis. Cerebrovascular accidents, stomach cancer, and liver disease contributed most to this decline. A remarkable decrease in transport accident mortality rates was also observed. The most salient increase in mortality was suicidal death. Mortality from homicide, pneumonia, and alcohol dependence increased during the economic crisis, but these accounted for a small proportion of total mortality.

CONCLUSIONS

Short-term mortality effects of the South Korean economic crisis were relatively small. It appears that any short-term effects of the economic decline were overwhelmed by the momentum of large declines in causes of death such as stroke, stomach cancer, and liver disease, which are probably related to exposures with much longer aetiological periods. However, this study focused on rather immediate mortality effects and follow-up studies are needed to elucidate any longer-term health effects of the South Korean economic crisis.

Prevalence of occult HBV infection among subjects with normal serum ALT levels in Korea

OBJECTIVE

To investigate the prevalence of occult HBV infection among subjects with normal serum ALT levels in South Korea.

METHODS

A total of 195 serum samples were collected from subjects without a past history of alcohol abuse and with normal serum ALT levels. They were negative for HBsAg, anti-HCV, and anti-HIV. HBV-DNA was detected from sera by nested polymerase chain reaction (PCR) using specific primers of the surface antigen region of the HBV genome. We performed a quantitation assay using hybrid capture II test to determine the levels of serum HBV-DNA.

RESULTS

HBV-DNA was detected in 31 of 195 subjects (16%). Prevalence of occult hepatitis B was significantly higher in the male subjects (23%) than in the female (8%), (P<0.05). We were able to detect HBV-DNA in 15% (7/47) even in which sera were all negative for anti-HBs and IgG anti-HBc. Serum HBV-DNA levels were as high as 10(5) copies/mL in 18 of 31 subjects (58%) with occult HBV infection.

CONCLUSIONS

The prevalence of occult HBV infection and their HBV-DNA levels were significantly high among subjects with normal serum ALT levels in South Korea. Thus, more meticulous attention should be given to prevent HBV transmission by blood transfusion or organ transplantation in endemic areas, and further studies on clinical implication and mechanism of occult HBV infection are required.

Seroprevalence of hepatitis B virus among health care workers in Korea

We studied the seroprevalence of HBsAg, anti-HBs and anti-HBc and the vaccination histories among health care workers (HCWs) at a large suburban referral hospital in Korea. The purpose of this study was to determine the immune status of HCWs against hepatitis B virus and we also wanted to prepare a practical guideline to protect HCWs from occupational exposure. During December, 2003, 571 HCWs (56 physicians, 289 nurses, 113 technicians and 113 aid-nurses) aged between 21 and 74 yr were included in the surveillance. The positive rates of HBsAg and anti-HBs were 2.4% (14/571) and 76.9% (439/571), respectively. The positive rate of anti-HBs was lower in the physician group, and this was associated with the male gender and older age. Of the 439 anti-HBs positive cases, 320 cases (73.1%) were anti-HBc negative and this was significantly associated with a past history of HBV vaccination. The distribution of the anti-HBs levels was not associated with age (except for HCWs in their sixties), gender or occupation. Our study revealed that the seroprevalence rates of HBsAg and anti-HBs in HCWs in Korea were not different from those of the general population. Based on this surveillance, we can make reasonable decisions in case of occupational exposure to hepatitis B virus.

Epidemiological characteristics of occupational blood exposures of healthcare workers in a university hospital in South Korea for 10 years

This study investigated the epidemiological characteristics of occupational blood exposures (OBEs) of healthcare workers (HCWs) in South Korea, and examined trends of OBEs after implementing blood exposure prevention (BEP) programmes. The study was conducted between 1 January 1992 and 31 December 2001 at a university-affiliated acute care hospital in Seoul. The BEP programmes comprised in-service education, hepatitis B virus (HBV) vaccination, and postexposure evaluation and prophylaxis. From 959 reported cases of OBEs, the crude incidence density (ID) was 2.62 cases per 100 person-years. The major risk groups for OBEs were physicians (ID 4.34) and new employees. The major type of OBE was from sharps injuries, including needlesticks (94.0%). OBE cases occurred more frequently during the spring (36.4%). The frequency of the serological tests of anti-hepatitis B surface antigen of HCWs changed significantly each year (P<0.05). The major serological risk for source patients was HBV (52.1%), but the risks for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) increased significantly each year (P<0.05). There were no seroconversion cases following OBEs among the tested HCWs. In summary, we established the epidemiological characteristics of OBEs in a South Korean university hospital, and reduced the risk of OBEs of major risk groups by BEP programmes. We also found an increase in the risk of HCV and HIV during the study period, suggesting that OBEs could be a serious threat to HCWs.

Cigarette smoking, alcohol drinking, hepatitis B, and risk for hepatocellular carcinoma in Korea

BACKGROUND

Liver cancer is one of the most common cancers worldwide, particularly in Asia and Africa, where infectious hepatitis and aflatoxin exposures are common. We conducted a prospective cohort study of liver cancer in Korea to assess the independent effects and interactions of smoking, alcohol consumption, and hepatitis B on risk of mortality from hepatocellular carcinoma.

METHODS

From a total of 1,283,112 men and women free of cancer at baseline, 3807 died from liver cancer during follow-up from 1993 to 2002. All participants reported their smoking and alcohol consumption, and hepatitis B surface antigen (HBsAg) status was documented for 47.2% of the participants. Relative risk and 95% confidence intervals (CIs) of mortality from hepatocellular carcinoma were calculated using proportional hazards models adjusted for age, alcohol drinking, diabetes, and HBsAg status.

RESULTS

Current smoking was associated with increased risk of mortality from hepatocellular carcinoma in men (RR = 1.4; 95% CI = 1.3 to 1.6) but not women (RR = 1.1; CI = 0.8 to 1.7). The relative risk of mortality from hepatocellular carcinoma for male HBsAg carriers was 24.3 (95% CI = 21.9 to 26.9) times that in HBsAg-negative males; the relative risk for HBsAg-positive women was 54.4 (95% CI = 24.8 to 119.5). Heavy alcohol drinking was associated with hepatocellular carcinoma mortality risk in the subgroup of men who were tested for HBsAg (RR =1.5; 95% CI = 1.2 to 2.0). There was no interaction among smoking, alcohol drinking, and HBsAg in terms of hepatocellular carcinoma mortality.

CONCLUSION

Cigarette smoking, heavy alcohol consumption, and HBsAg were independently associated with increased risk of mortality from hepatocellular carcinoma but did not interact synergistically. The relatively higher increase in mortality from hepatocellular carcinoma in HBsAg-seropositive women compared with men merits further research.

International adoption: infectious diseases issues

Nearly 220,000 children have been adopted from other countries by American parents since 1986. Approximately 65,000 children have arrived from China and Russia, mostly in the past 6 years. Most of these children reside in orphanages before adoption, where they may experience malnutrition, environmental deprivation, neglect, and exposure to infectious diseases. After arrival to the United States, international adoptees should undergo specialized screening evaluation for infectious diseases and other conditions. Infectious conditions of special concern include hepatitis B and C, syphilis, human immunodeficiency virus infection, tuberculosis, and presence of intestinal parasites. Before the adoption occurs, the infectious disease consultant may be asked to assist the primary care provider and the adoptive family with advice about travel and review of preadoptive medical records. After the adoption, the infectious diseases consultant may be asked to assess the adequacy of the child's vaccination record from the birth country and to assist in screening, evaluation, and management of infectious diseases.

Global epidemiology of hepatitis B virus

The burden of hepatitis B virus (HBV) disease and efforts to control infection will determine the future size of the population requiring treatment of HBV infection. To quantify the current prevalence of HBV infection and to reexamine the epidemiology of HBV infection, a structured review was conducted that focused on available primary literature for over 30 countries worldwide. The prevalence of chronic HBV infection continues to be highly variable, ranging over 10% in some Asian and Western Pacific countries to under 0.5% in the United States and northern European countries. The current global estimate of the number of HBV infected individuals is 350 million. Routes of transmission include vertical (mother to child or generation to generation through close contact and sanitary habits), early life horizontal transmission (through bites, lesions, and sanitary habits), and adult horizontal transmission (through sexual contact, intravenous drug use, and medical procedure exposure) and are evident to varying degrees in every country. Younger age at acquisition of infection continues to be the most important predictor of chronic carriage. However, the choice of serologic markers, temporal influences, and representativeness of the study population limit comparability of HBV seroprevalence results. HBV vaccination programs will decrease the future global burden of HBV infection and evidence of reduced burden is mounting in country-specific populations, but vaccination programs have still not been implemented in all countries, thereby maintaining reservoirs of infection and continued HBV transmission. Regardless of vaccination, large numbers of persons are infected with HBV or will become infected. Preventing the most severe HBV disease consequences in infected individuals, such as cirrhosis and hepatocellular carcinoma, will require appropriate therapeutic agents.

Current antiviral therapy for chronic hepatitis B

During the past decade, major breakthroughs have been achieved in treatment of chronic hepatitis B. Currently, three therapeutic agents are approved for chronic hepatitis B: interferon-alpha, lamivudine and adefovir dipivoxil. In patients with HBeAgpositive chronic hepatitis B, all of these drugs achieve HBeAg loss (24-33%) and anti-HBe seroconversion (12-30%) rates that are superior to those observed in untreated controls. Interferon-alpha has several drawbacks, such as the parenteral administration and the development of frequent and potentially serious side effects. Lamivudine is a safe drug with rare and generally mild side effects. Lamivudine induces an initial virological remission in 70-90% of patients, but only 30-40% of patients remain in remission after the third year due to progressively increasing viral resistance. The main advantage of adefovir dipivoxil is the rare emergence of resistance, which has been identified in less than 2% of patients at 2 yr of treatment. Adefovir is also effective against lamivudine-resistant strains. This review will focus on the natural history and recently gained knowledge on the treatment of chronic hepatitis B.