Incidence and seroprevalence of hepatitis A virus infections among young Korean soldiers

Prevalence of hepatitis A in the capitals of the States of North, Southeast and South regions of Brazil: decrease in prevalence and some consequences

Hepatitis A virus (HAV) infection has been considered one of the leading causes of acute hepatitis. The aim of the present study was to estimate the prevalence of HAV among children and adolescents in a population-based study in the capitals of the States of the North, Southeast and South of Brazil and identify predictive factors for the infection. A multi-stage sampling was used to select subjects aged between 5-9 and 10-19 years. Individual and household levels aside from the level of variables in the areas were collected. The outcome was the total IgG antibodies to HAV levels detected using a commercial Enzyme Immuno Assay (EIA). The associations between HAV and the independent variables were assessed using the odds ratio. A multilevel analysis was performed by GLLAMM using the Stata software. The prevalence of HAV infection in the 5-9 and 10-19 age groups was 28.7% and 67.5%, respectively for the North, 20.6% and 37.7%, for the Southeast and 18.9% and 34.5% for the South Region. The prevalence of HAV increased according to age in all sites. Variables related to education at the individual level (North and South), family and area level (South and Southeast) and family income level (Southeast and South) were independently associated with HAV infection. This emphasizes the need for individualized strategies to prevent the infection.

Current status and strategies for the control of viral hepatitis A in Korea

Hepatitis A virus is one of the most frequent causes of foodborne infection, which is closely associated with sanitary conditions and hygienic practices. The clinical spectrum of acute hepatitis A is wide, ranging from mild case without any noticeable symptoms to severe case with acute liver failure leading to mortality. The severity and outcome are highly correlated with age at infection. In developing countries, most people are infected in early childhood without significant symptom. Ironically, in area where sanitary condition has improved rapidly, adults who do not have immunity for viral hepatitis A (VH-A) in early childhood is accumulating. Adults without immunity are exposed to risks of symptomatic disease and large outbreaks in society. In Korea, where hygiene has improved rapidly, acute hepatitis A is a significant health burden that needs to be managed with nationwide health policy. The incidence of symptomatic VH-A has increased since 2000 and peaked in 2009. Korea has designated hepatitis A as a group 1 nationally notifiable infectious disease in 2001. Since 2001, mandatory surveillance system has been established to detect every single case of acute hepatitis A. Universal, nationwide vaccination program for newborns was introduced in 2015. In this review, we will present the current epidemiologic status of viral hepatitis A, and evaluate the effectiveness of the current nationwide strategies for the control of viral hepatitis A in Korea. Furthermore, we presented some action proposals that can help eliminate viral hepatitis A, which is a significant health burden in Korea.

Antibodies against Hepatitis A and Hepatitis B Virus in Intravenous Immunoglobulin Products

The worldwide seroprevalence of hepatitis A virus (HAV) and hepatitis B virus (HBV) has changed over the last two decades, indicating a declining incidence of HAV and HBV infections. Therefore, vaccinations against HAV and HBV are recommended for unimmunized people before traveling to an endemic area. Unfortunately, primary antibody deficiency (PAD) patients can only obtain humoral immunity through intravenous immunoglobulin G (IVIG) replacement and not from vaccination because of a defect in antibody production. However, few studies have analyzed the titers of antibodies against HAV or HBV in IVIG products. In this study, the titers of anti-HAV and anti-HBs antibodies were measured in nineteen lots of IVIG products from five manufacturers from three countries (A, B from Korea; C, D from Japan; and E from the USA), and trough titers in plasma were estimated. Concentrations of anti-HAV antibody ranged from 1,888-8,927 mIU/mL and estimated trough titers exceeded the minimal protective value in all evaluated IVIG products. Concentrations of anti-HBs antibody ranged from 438-965 mIU/mL in products A and B and were 157, 123, and 1,945 mIU/mL in products C, D, and E, respectively. Estimated trough titers in products A, B, and E exceeded the minimal protective value but those in products C and D did not reach this threshold. These data demonstrated that available IVIG products generally provide sufficient antibodies against HAV and HBV to protect patients with PAD, although the trough concentrations of anti-HBs antibody in two IVIG products did not reach the minimum protective value.

Vaccination policy in Korean armed forces: current status and future challenge

Infectious diseases have historically resulted in suspended or cancelled military operations. Vaccination for disease prevention is a critical component of the military's force readiness doctrine. Until recently, Korea had not recognized the importance of vaccinating military personnel. However, a 2011 meningococcal disease outbreak at an army recruit training center led to dramatic changes in the paradigm of traditional medical practice in the Korean armed forces. A new vaccination policy was formed by a 2012 Military Healthcare Service Act. Since then, Neisseria meningitidis, hepatitis A, and measles-mumps-rubella vaccines have been routinely administered to all new recruits early in basic training to ensure protection against these diseases. All active-duty soldiers also receive seasonal influenza vaccination annually. Despite quantitative improvements in vaccination policies, several instances of major infectious diseases and adverse vaccine reactions have threatened soldier health. In the future, vaccination policies in the Korean armed forces should be based on epidemiologic data and military medical research for vaccine use and safety management.

The costs of hepatitis A infections in South Korea

OBJECTIVES:

The incidence of hepatitis A infections among young adults has recently increased in South Korea. Although universal vaccination has often been suggested to mitigate the problem, its rationale has not been well-understood. Estimating the societal costs of hepatitis A infections might support the development of intervention strategies.

METHODS:

We classified hepatitis A infections into eight clinical pathways and estimated the number of occurrences and cost per case for each clinical pathway using claim data from National Health Insurance and several national surveys as well as assumptions based on previous studies. To determine the total costs of a hepatitis A infection, both direct and indirect costs were estimated. Indirect costs were estimated using the human-capital approach. All costs are adjusted to the year 2008.

RESULTS:

There were 30,240 identified cases of hepatitis A infections in 2008 for a total cost of 80,873 million won (2.7 million won per case). Direct and indirect costs constituted 56.2% and 43.8% of the total costs, respectively. People aged 20-39 accounted for 71.3% of total cases and 74.6% of total costs. Medical costs per capita were the lowest in the 0-4 age group and highest in the 20-29 age group.

CONCLUSIONS:

This study could provide evidence for development of cost-effective interventions to control hepatitis A infections. But the true costs including uncaptured and intangible costs of hepatitis A infections might be higher than our results indicate.

Prognostic indicators for acute liver failure development and mortality in patients with hepatitis A: consecutive case analysis

PURPOSE

Due to the seroepidemiological shift in hepatitis A (HA), its severity, mortality, and complications have increased in recent years. Thus, the aim of this study was to identify predictive factors associated with poor prognosis among patients with HA.

MATERIALS AND METHODS

A total of 304 patients with HA admitted to our institution between July 2009 and June 2011 were enrolled consecutively. Patients with complications defined as acute liver failure (ALF) were evaluated, and mortality was defined as death or liver transplantation.

RESULTS

The mean age of patients (204 males, 100 females) was 32 years. Eighteen (5.9%) patients had progressed to ALF. Of the patients with ALF, 10 patients (3.3%) showed spontaneous survival while 8 (2.6%) died or underwent liver transplantation. Multivariate regression analysis showed that Model for End-Stage Liver Disease (MELD) and systemic inflammatory response syndrome (SIRS) scores were significant predictive factors of ALF. Based on receiver operating characteristics (ROC) analysis, a MELD≥23.5 was significantly more predictive than a SIRS score≥3 (area under the ROC: 0.940 vs. 0.742, respectively). In addition, of patients with a MELD score≥23.5, King's College Hospital criteria (KCC) and SIRS scores were predictive factors associated with death/transplantation in multivariate analysis.

CONCLUSION

MELD and SIRS scores≥23.5 and ≥3, respectively, appeared to be related to ALF development. In addition, KCC and SIRS scores≥3 were valuable in predicting mortality of patients with a MELD≥23.5.

Seroepidemiology of hepatitis a in South Korea: a nationwide study by the Eone Reference Laboratory

Background

We evaluated the recent prevalence of serologic markers of hepatitis A virus (HAV) in South Korea.

Methods

The study data were the results of 60 126 anti-HAV (total) tests and 30 786 anti-HAV IgM tests that were performed during April 2009 through March 2010 by the Eone Reference Laboratory at the request of 1935 institutions throughout Korea.

Results

The overall positivity rate was 51.06% on the anti-HAV (total) test and 11.20% on the anti-HAV IgM test. As compared with the other age groups the rate of anti-HAV (total) positivity was significantly lower (P < 0.001), and the rate of anti-HAV IgM positivity was significantly higher (P < 0.001), among Koreans aged 11 to 40 years. The seroprevalence of anti-HAV IgM significantly differed according to region but not by referral date.

Conclusions

This was the largest nationwide study in South Korea by 1 laboratory, and it provides useful recent baseline data on hepatitis A in Asia. The findings suggest that active immunization of younger Koreans should be made a priority.

A nationwide seroprevalence of total antibody to hepatitis A virus from 2005 to 2009: age and area-adjusted prevalence rates

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.

Prevalence of IgG anti-HAV in patients with chronic hepatitis B and in the general healthy population in Korea

Background/Aims

Few studies have investigated hepatitis A virus (HAV) seroepidemiology in Koreans with chronic liver disease (CLD). This study compared the prevalence of IgG anti-HAV between the general healthy population and patients with hepatitis B virus-related CLD (HBV-CLD), with the aim of identifying predictors of HAV prior exposure.

Methods

In total, 1,319 patients were recruited between June 2008 and April 2010. All patients were tested for IgG anti-HAV, hepatitis B surface antigen (HBsAg), and antibodies to hepatitis C virus. The patients were divided into the general healthy population group and the HBV-CLD group based on the presence of HBsAg. The seroprevalence of IgG anti-HAV was compared between these two groups.

Results

The age-standardized seroprevalence rates of IgG anti-HAV in the general healthy population and patients with HBV-CLD were 52.5% and 49.1%, respectively. The age-stratified IgG anti-HAV seroprevalence rates for ages ≤19, 20-29, 30-39, 40-49, 50-59, and ≥60 years were 14.3%, 11.2%, 45.5%, 90.5%, 97.6% and 98.3%, respectively, in the general healthy population, and 0%, 9.8%, 46.3%, 91.1%, 97.7%, and 100% in the HBV-CLD group. In multivariate analysis, age (<30 vs. 30-59 years: OR=19.339, 95% CI=12.504-29.911, P<0.001; <30 vs. ≥60 years: OR=1060.5, 95% CI=142.233-7907.964, P<0.001) and advanced status of HBV-CLD (OR=19.180, 95% CI=4.550-80.856, P<0.001) were independent predictors of HAV prior exposure.

Conclusions

The seroprevalence of IgG anti-HAV did not differ significantly between the general-healthy-population and HBV-CLD groups. An HAV vaccination strategy might be warranted in people younger than 35 years, especially in patients with HBV-CLD.

Control of hepatitis A by universal vaccination of children and adolescents: an achieved goal or a deferred appointment?

Temporal trends of Hepatitis A cases and vaccination coverage data against Hepatitis A Virus have been investigated to analyse the impact of the universal routine vaccination strategy more than 10 years from its introduction in Puglia (region of Southern Italy). The basic reproductive number (R(0)) before vaccination introduction and the effective reproductive number (R(e)) after introduction have been calculated. A progressive decrease in incidence has been recorded in Puglia during last 10 years. Vaccination coverage is actually 64.8% (95% CI: 52.7-76.9%) for children aged 12-24 months and of 67.6% (95% CI: 58.4-76.8%) for 12-year-old adolescents. R(0) estimated in 1996 was 2.01; actually R(e) is 0.651. Theoretical age at infection is 31.82 years. Universal routine vaccination aimed at the control of direct transmission remains the milestone in the strategy for the containment of the disease in settings at an intermediate level of endemicity.

Vaccination rate and seroepidemiology of hepatitis a in chronic-hepatitis-B-infected individuals in the korean army

BACKGROUND/AIMS

Vaccination against hepatitis A virus (HAV) is recommended for patients with chronic hepatitis B (CHB), since they are potentially at an increased risk of HAV-related morbidity and mortality. However, little is known about the adherence to these recommendations in the community. This study evaluated the current vaccination status and immunity against HAV among Korean military soldiers with CHB.

METHODS

We performed a prospective study of Korean military soldiers from August 2008 to January 2009. We enrolled 96 soldiers with CHB on a consecutive basis. We assessed their vaccination history and the presence of anti-HAV immunoglobulin G (IgG).

RESULTS

The HAV vaccination rate of the soldiers enrolled in our study was 2% (2 of the 96 soldiers). The seroprevalence rates of anti-HAV IgG among military soldiers without a vaccination history were 0%, 50%, and 100% for those aged 19-29 years (n=71), 30-39 years (n=8), and 40 years or older (n=15), respectively (p<0.001).

CONCLUSIONS

The HAV vaccination rate is very low among military soldiers. Public health efforts aimed at raising awareness about HAV vaccination in patients with CHB should be strongly encouraged.

[Seroprevalence of IgG anti-HAV in hospital employees below 40 years old]

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 employees (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 employees below the early thirties.

[An epidemiological analysis of hepatitis A virus serologic markers during the recent four years in Korea]

BACKGROUND

To establish effective preventive measures for hepatitis A virus (HAV) infection, a nationwide epidemiologic study on seroprevalence of anti-HAV and the disease prevalence is needed. The aim of this study was to analyze the recent sero-epidemiological changes of hepatitis A markers in Korea.

METHODS

The results of 11,068 anti-HAV total and 32,360 anti-HAV IgM tests by electro-chemiluminescence immunoassay (ECLIA) that had been requested in recent four years (2005-2008) to a reference medical laboratory from 1,699 institutions nationwide were retrospectively analyzed according to the distribution of year, sex, and age groups.

RESULTS

The overall positive rate of anti-HAV total was 62.8%. The overall positive rate of anti-HAV IgM was 11.0%, showing a significantly increasing trend by year: 7.7%, 10.9%, 8.9%, and 14.3% in 2005, 2006, 2007, and 2008, respectively (P<0.0001). The positive rate of anti-HAV IgM was higher in male than in female subjects (11.8% vs 10.0%, P<0.0001), and 81.8% (2,916/3,566) of the anti-HAV IgM positive results were observed in the age groups of 21-40 yr. The annual positive rates of anti-HAV total and anti-HAV IgM showed significantly decreasing and increasing trends, respectively, in the age groups of > or = 21 yr.

CONCLUSION

In accordance with a decreasing sero-positivity of anti-HAV total, the prevalence of acute hepatitis A virus infection has been considerably increased during the recent four years in the age groups of > or = 21 yr. The results of this study could be used effectively as a basic data for establishing effective preventive measures for hepatitis A including vaccination in these susceptible age groups.

[Hepatitis A virus seropositivity among healthcare workers at a university hospital in Korea]

BACKGROUND

Healthcare workers (HCW) are known as a risk group of hepatitis A virus (HAV) infection and vaccination of this group against HAV has been suggested. However, the seroprevalence of HAV antibody among HCW in Korea has not been reported. We investigated the seropositivity of HAV antibody in HCW, to obtain a baseline data.

METHODS

We measured serum total HAV antibody using chemiluminescent immunoassay (ADVIA Centaur, Germany) in 174 HCW at one university hospital in Seoul, Korea.

RESULTS

Serum HAV antibody was positive in 48 (27.6%) of 174 subjects tested. The seropositivity of HAV antibody was significantly increased with increasing age: 21.1% (26/123), 55% (22/40), and 100% (11/11) in the age groups of 20's, 30's, and 40's, respectively (P<0.001). However it was not significantly different among different occupations (physicians 38%, nurses 24.6%, other workers 31.4%, P=0.376) and work places (medical ward 29.1%, pediatric ward 25.9%, emergency room 34.4%, laboratory 0%, P=0.140). The seroprevalence rate of HAV antibody in the age groups of 20's and 30's in this study was not higher than that of previous studies on non-HCW populations in Korea since 2006.

CONCLUSIONS

The seroprevalence of HAV antibody among HCW in the age groups of 20's and 30's in a Korean hospital was not higher than that of non-HCW populations, and the seropositivity increased with increasing age. Further studies are needed for the age-specific strategy for vaccination, considering the increased risk of exposure in HCW to HAV infection in hospital environment with the increase of symptomatic patients with HAV.

Molecular epidemiology of hepatitis A virus in the South-East area of Gyeonggi-do in Korea

PURPOSE

Hepatitis A virus (HAV) has been a leading cause of acute hepatitis in Korea. The reported genotypes of acute hepatitis A in Korea are the subgenotype IA and IB. The aim of the present study is to investigate HAV genotypes in the south-east area of Gyeonggi-do in Korea.

MATERIALS AND METHODS

From June 2004 to June 2006, 46 acute hepatitis A patients were enrolled prospectively. All had sporadic acute hepatitis A patients. All suspected cases of acute hepatitis A were tested for IgM anti-HAV antibodies. We sequenced 168 bp of nucleotides of the putative VP1/P2A junction and determined the HAV genotype with reverse transcriptase polymerase chain reaction. The clinical and laboratory results of all patients were recorded.

RESULTS

HAV-ribonucleic acid (RNA) was detected in 41 samples out of 46 samples. Among the 41 samples, 25 (60%) were shown to have subgenotype IIIA and the other 16 (40%) were subgenotype IA. Several amino acid substitutions were found.

CONCLUSION

In these HAV sporadic cases, IIIA and IA were identified, and this may reflect co-circulation of various genotypes in Korea. This study provides valuable new data on the genetic distribution of HAV and important information to help design appropriate public health measures.

Sero-epidemiology of hepatitis A virus infection among healthcare workers in Korean hospitals

Hepatitis A virus (HAV) has been increasingly reported in Korea as has an outbreak in Korean healthcare workers (HCWs). This 2008 study evaluated the sero-epidemiology of HAV infections among 3696 HCWs in four Korean hospitals. HCWs were tested for immunoglobulin G anti-HAV antibodies using commercially available kits. Data including demographic characteristics, occupation, workplace and serological status for other hepatitis viruses were collected. Statistical analyses were conducted to identify variables related to HAV seropositivity. Among the 3696 participants, 2742 (74%) were women and the majority (96%) were aged 20-39 years (median: 28; range: 19-68). Eighteen percent were physicians, 46% nurses, 10% nurses' aides, 11% paramedical technicians and 15% administrative staff. Seropositivity for HAV significantly increased with age (P<0.001): 1.8% for < or =24 years, 14.7% for 25-29 years, 41.8% for 30-34 years, 75.5% for 35-39 years, and 93.7% for > or =40 years. Among those aged 20-39 years, age-specific HAV seroprevalence was significantly lower in physicians than in the other occupational groups (P<0.001). In Korea, mass vaccination to HCWs aged < or =29 years or screening for seropositivity and vaccinating non-immune subjects aged 30-39 years should be considered, especially in physicians.