PURPOSE: Assessing the immunogenicity of a single dose of hepatitis A virus (HAV) vaccines is important because some people receive only a single dose. However, previous studies have shown variable results and have not examined the effects of demographic characteristics other than gender. This study was performed to examine the immunogenicity of a single dose of HAV vaccine according to the vaccine type and demographic characteristics in young adults. MATERIALS AND METHODS: Seronegative medical school students were randomly allocated to receive either Havrix or Epaxal. RESULTS: After approximately 11 months, the seroconversion rate in 451 participants was 80.7%. In men, the Havrix group showed a significantly higher seroconversion rate (81.9%) than the Epaxal group (69.2%), whereas both vaccine groups showed similarly high immunogenicity in women (Havrix: 90.1%, Epaxal: 92.9%; P for interaction=0.062). According to the results of a multivariate analysis, Epaxal showed significantly lower immunogenicity than Havrix only in men. Age, obesity, drinking, smoking, and follow-up time did not significantly affect seroconversion in either gender. CONCLUSION: The seroconversion rate of single-dose HAV vaccines was low in men, particularly in those who received Epaxal. Our results suggest that gender effects should be considered when comparing the immunogenicity of different HAV vaccines.
Adolescent ; Adult ; Female ; Hepatitis A/*immunology/*prevention & control ; Hepatitis A Vaccines ; Hepatitis A Virus, Human/*immunology/*pathogenicity ; Humans ; Male ; Young Adult

INTRODUCTIONSingapore has experienced remarkable socioeconomic progress over the last few decades, with a corresponding rise in standards of sanitation and living conditions. We undertook a study to describe its epidemiological trends of hepatitis A over the last 2 decades.

MATERIALS AND METHODSWe analysed the epidemiological data on all laboratory-confirmed cases of hepatitis A from 1990 to 2009. We also described 3 outbreaks which occurred in 1991, 1992 and 2002. To determine the changing prevalence of hepatitis A virus (HAV) infection, we compared the findings from a seroepidemiological study conducted in 1993 with earlier surveys in 1975 and 1984/1985.

RESULTSThe incidence of indigenous hepatitis A cases per 100,000 population declined significantly from 1.8 in 1989 to 0.7 in 2009, and more than half were imported. While majority of the imported cases were Singapore residents, the proportion of imported cases among Singapore residents had decreased significantly. Most of the Singapore residents contracted the disease from Southeast Asia and the Indian subcontinent. The overall prevalence of HAV infection in the population declined from 31.8% in 1984/85 to 25.9% in 1993.

CONCLUSIONThe incidence and seroprevalence of hepatitis A in Singapore are comparable to other developed countries. As Singapore is situated in a region highly endemic for HAV, it is very vulnerable to the introduction of the disease because of the high volume of regional travel and import of food, especially shellfish. While we note that there have been no further shellfish-associated outbreaks since 2002, sustained vigilance, strict control of food import by the authorities and public health education on the risk of consuming shellfish, especially cockles, raw and half-cooked, should be maintained.

Adolescent ; Adult ; Child ; Child, Preschool ; Disease Outbreaks ; Female ; Hepatitis A ; epidemiology ; etiology ; Hepatitis A Virus, Human ; isolation & purification ; Humans ; Immunoglobulin G ; immunology ; Infant ; Male ; Middle Aged ; Seroepidemiologic Studies ; Shellfish ; virology ; Singapore ; epidemiology ; Young Adult

BACKGROUND/AIMS: Acute hepatitis A (HAV) is markedly increasing recently on. Some patients with acute hepatitis A show severe clinical course. The seroprevalence rate of IgG anti-HAV has been changing with the regions and the times. Vaccination and seroconversion rate of HAV are not well known. In this study, we aimed to study the difference of seroprevalence rate of IgG anti-HAV according to various clinical factors and to know the vaccination rate and seroconversion rate below 10 years old in the central region of South Korea including Cheonan city. METHODS: Seven hundred seventy two subjects were included in the study from January to September 2009. We analyzed seroprevalence rate of IgG anti-HAV according to sex, age, region, and other viral markers. We interviewed the history of vaccination(1st, 2nd) and analyzed seroconversion rate according to vaccination time below 10 years old. RESULTS: The total seroprevalence rate of IgG anti-HAV was 65.3%. The seroprevalence rate of IgG anti-HAV rate in 2nd, 3rd, and 4th decade was very low (1.9%, 18.8%, 44.8%). The vaccination rate of children was about 50%. The seroconversion rate after 1st, and 2nd vaccination were 85%, 96%. CONCLUSIONS: Catch-up vaccination for teenagers and young adults is needed. Immunizing children with HAV vaccine as a routine schedule should be considered.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Child, Preschool ; Female ; Hepatitis A/*epidemiology/prevention & control ; Hepatitis A Antibodies/*blood ; *Hepatitis A Vaccines ; Hepatitis A Virus, Human/immunology ; Humans ; Immunoglobulin G/blood ; Male ; Middle Aged ; Republic of Korea ; Seroepidemiologic Studies

BACKGROUND/AIMS: Recent outbreak of hepatitis A in Korea is clearly related to the epidemiological shift of hepatitis A virus (HAV). However, nationwide seroprevalence data have been limited. This study estimated the nationwide, age- and area-adjusted anti-HAV prevalence from 2005 to 2009. METHODS: Retrospective analysis of the results of total anti-HAV test in 25,140 cases which were requested by 1,699 medical institutions throughout the nation to Seoul Clinical Laboratory from Jan. 1 2005 to Dec. 31 2009 was performed. The estimated seroprevalence was adjusted by area and age of the standard population based on the 2005 Census data from Korea National Statistical Office. RESULTS: The area-adjusted anti-HAV prevalence in the children younger than 10 years were 33.4% in 2005 and 69.9% in 2009. The most susceptible age groups to HAV infection during the last 5 years were teenagers and the young adults in their age of twenties. The area-adjusted seroprevalence in 2009 were 11.9% in the age group of 20-29 years, 23.4% in the age group of 10-19 years, 48.4% in the age group of 30-39 years. The population in 40-49 years showed geographically different seroprevalence with the lowest rate in Seoul (80%). CONCLUSIONS: The most susceptible age group to HAV infection is 10-29 years, while the young children less than 10 years showed about 70% seropositivity. The changing seroepidemiology should be monitored continuously for the proper vaccination and patient care.
Adolescent ; Adult ; Age Factors ; Aged ; Child ; Child, Preschool ; Female ; Hepatitis A/*epidemiology ; Hepatitis A Antibodies/*blood ; Hepatitis A Virus, Human/immunology ; Humans ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Retrospective Studies ; Seroepidemiologic Studies

BACKGROUND/AIMS: Hepatitis A is an acute infectious disease transmitted by fecal-oral route. As the incidence of hepatitis A has been increased in Gwangju and Chonnam province of Korea recently, the number of hepatitis A patients in hospital employees has also increased. Thus, we investigated the seroprevalence of IgG anti-HAV in hospital employees below 40 years old. METHODS: We analysed the seroprevalence of anti-HAV IgG from 1,002 Chonnam national university hospital empolyees (men: 190, women: 812) who were below 40 years old. The age group was divided by 5 years; 21-25 years old 199 (19.9%), 26-30 years old 426 (42.5%), 31-35 years old 215 (21.5%), 36-40 years old 162 (16.1%). RESULTS: Overall seropositive rate of IgG anti-HAV was 32.8% (329/1,002). The seropositive rate of men was 40.5% (77/190) and that of women was 31.0% (252/812). The seropositive rates of each age group were 1.5% (3/199) in 21-25 years old, 21.6% (92/426) in 26-30 years old, 48.4% (104/215) in 31-35 years old, and 80.2% (130/162) in 36-40 years old. The seropositivity rate of the high risk group (doctors, nurses, technicians) was 28.9% (234/809). CONCLUSIONS: The seropositive rate of IgG anti-HAV was the lowest in early twenties of hospital employees and below 50% in early thirties. Therefore, hepatitis A vaccination may be warranted in the hospital empolyees below the early thirties.
Adult ; Female ; Hepatitis A/*epidemiology ; Hepatitis A Antibodies/*blood ; Hepatitis A Virus, Human/immunology ; Hospitals ; Humans ; Immunoglobulin G/*blood ; Male ; Occupational Diseases/*epidemiology ; *Personnel, Hospital ; Seroepidemiologic Studies ; Young Adult

OBJECTIVETo investigate the seroprevalence of anti-HAV IgG in adults of 4 cities in China.

METHODSSerum samples were collected from 2390 local residents aged between 20 to 88 years from Beijing, Shanghai, Wuhan and Guangzhou. The anti-HAV IgG in sera was detected with a microparticle enzyme immunoassay (MEIA).

RESULTSThe anti-HAV IgG seroprevalence in female of 30 to 39 years in Beijing (64.58%, 62/96) was higher than that in male (45.57% 36/79)) (x(2) = 6.358, P = 0.012). It increased with age in adults of Beijing and Guangzhou. The rates were 54.22 % (90/166), 56.00% (98/175) and 67.18% (88/131) for the 20-, 30- and 40-49 age groups in Beijing (x(2) = 4.76, P = 0.03); and 52.83% (56/106), 52.50% (63/120), 82.46% (94/114), 89.80% (88/98) and 96.77% (60/62) for the 20-, 30-, 40-, 50- and 60-88 age groups in Guangzhou, respectively (x(2) = 72.58, P less than 0.01). This trend was not found in Shanghai and Wuhan (x2 = 0.96, 2.99; P = 0.33, 0.08 respectively). The seroprevalence rates of anti-HAV IgG in the 20 to 39 age group of Beijing, Shanghai, Guangzhou and Wuhan were 55.13% (188/341), 63.93% (429/671), 52.65% (119/226) and 78.37% (308/393), respectively.

CONCLUSIONThe seroprevalence rates of anti-HAV IgG in young adults aged 20 to 39 years of the four cities are relatively low, and HAV vaccination should be suggested for the susceptible population of this age group in China.

Adult ; Age Distribution ; Aged ; Aged, 80 and over ; China ; epidemiology ; Female ; Hepatitis A ; epidemiology ; immunology ; prevention & control ; Hepatitis A Antibodies ; blood ; Hepatitis A Virus, Human ; immunology ; Humans ; Immunoglobulin G ; blood ; Male ; Middle Aged ; Seroepidemiologic Studies ; Sex Distribution ; Urban Population ; Young Adult

Several research groups have recently reported that persistent GB virus C (GBV-C) co-infected with human immunodeficiency virus (HIV) leads to slower AIDSs disease progression than HIV-1 infection alone. However, these findings were not confirmed by several other studies. To investigate the association between GBV-C replication and plasma HIV loads and CD4+ T cell counts, 203 HIV-1 positive former blood/plasma donors(FBDs) were enrolled from Fuyang city of Anhui Province in China. Plasma specimens were collected from them and were tested for GBV-C using RT-PCR and ELISA. Out of 203 specimens, 52 (25.6%) cases were positive for GBV-C, including 35 male (67.3%) and 17 female (32.7%) cases. No significant association was identified between GBV-C infection and CD4+ T-cell counts or between GBV-C infection and HIV viral loads. Since all the subjects studied were naive to ART, the influence of therapy on AIDS disease progression was ruled out in this study. Overall, our data indicated that HIV-1 positive male FBDs were prone to be infected, GBV-C coinfection with HIV-1 does not significantly influence HIV/AIDS disease progression during the late stage of chronic HIV-1 infection.
Acquired Immunodeficiency Syndrome ; complications ; immunology ; virology ; Adult ; Aged ; CD4 Lymphocyte Count ; Disease Progression ; Female ; Flaviviridae Infections ; immunology ; virology ; GB virus C ; HIV-1 ; physiology ; Hepatitis, Viral, Human ; immunology ; virology ; Humans ; Male ; Middle Aged ; RNA, Viral ; blood ; Virus Replication

Adult ; Aged ; Bile Duct Neoplasms ; blood ; virology ; Biomarkers ; blood ; DNA, Viral ; blood ; Female ; Hepatitis B Antibodies ; blood ; Hepatitis B Surface Antigens ; blood ; metabolism ; Hepatitis B virus ; genetics ; immunology ; Hepatitis, Viral, Human ; blood ; virology ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Liver ; metabolism ; pathology ; virology ; Male ; Middle Aged

BACKGROUND/AIMS: The purpose of this study was to characterize the clinical features of acute hepatitis A in Seoul and Gyeonggi province during the recent 2 years. METHODS: We reviewed the medical records of 222 patients who were diagnosed as acute hepatitis A between August 2005 and March 2007 at the Konkuk University Hospital and Korea University, Ansan Hospital. The clinical manifestation, serological tests, and image findings were analyzed. RESULTS: Median age of the patients was 28.1 years and the age groups of highest incidence were the second and third decade. The frequent symptoms were anorexia (66.4%), fatigue (49.2%), fever (47.7%), and abdominal discomfort (42.5%). Fourteen cases (6.3%) showed renal insufficiency, and hemodialysis was performed in one. Cholestatic hepatitis in 2 cases, relapsing hepatitis in 4 cases and prolonged hepatitis in 13 cases were observed. However, there was no case of fulminant hepatitis or death. The underlying diseases including chronic hepatitis B, diabetes mellitus and thyroid disorder did not affect the disease severity of hepatitis A. IgM anti-HAV was not detected initially in 6.7% of the patients. Anti-HEV (IgM) was detected simultaneously in 3 of 150 patients. CONCULSIONS: The age of patients with acute hepatitis A has been increased in the recent years. Most patients recovered uneventfully. However, unusual patterns of severe hepatitis and renal insufficiency occurred in considerable number of cases. Follow-up serologic test for IgM anti-HAV is needed in seronegative cases with hepatitis A
Acute Disease ; Adolescent ; Adult ; Age Distribution ; Child ; Child, Preschool ; Female ; Hepatitis A/*diagnosis/immunology ; Hepatitis A Antibodies/metabolism ; Hepatitis A Virus, Human/immunology ; Humans ; Immunoglobulin M/blood ; Male ; Middle Aged ; Serologic Tests ; Suburban Population

BACKGROUND/AIMS: Recently, the incidence of acute hepatitis A has increased nationwide and is related to the low rate of IgG anti-HAV. This study compared the prevalence of IgG anti-HAV in two university hospitals located in a large city and in a small city including a rural region according to age, gender, and the year of diagnosis. METHODS: IgG anti-HAV was measured in a total of 4299 patients, who visited Seoul or Guri Hanyang University Hospital between January 2002 and December 2006. RESULTS: The positive rates of the antibody in Seoul and Guri hospitals were 52.7% vs 57.1% in under the age of 1, 40.7% vs 42.2% in age of 1 to 4, 31.8% vs 30.3% in age of 5 to 9, 24.8% vs 27.1% in age of 10 to 14, 11.6% vs 18.2% in age of 15 to 19, 23.0% vs 20.3% in age of 20 to 24, 40.5% vs 42.9% in age of 25 to 29, 67.5% vs 75.0% in age of 30 to 34, 86.5% vs 88.1% in age of 35 to 39, 95.3% vs 93.6% in age of 40 to 44, 97.0% vs 98.7% in age of 45 to 49, and 98.5% vs 98.6% in patients who were more than 50, respectively. The positive rates of the antibody were not significantly different between two sites according to each age group and gender. CONCLUSIONS: The results confirmed the low rates of IgG anti-HAV, particularly in the ages of 10-24 that match the age group of recently increased incidence of acute hepatitis A nationwide. Therefore, measurement of the antibody and vaccination should be considered in this age group.
Adolescent ; Adult ; Aged ; Child ; Child, Preschool ; Female ; Hepatitis A/*epidemiology ; Hepatitis A Antibodies/*blood ; Hepatitis A Virus, Human/immunology ; Hospitals ; Humans ; Immunoglobulin G/*blood ; Infant ; Korea/epidemiology ; Male ; Middle Aged ; Rural Population ; Seroepidemiologic Studies ; Urban Population