Hepatitis A Virus Seroprevalence Research Articles

Seroepidemiology of hepatitis a in the croatian population.

Hepatitis A virus (HAV) has a worldwide distribution, although this distribution tends to be uneven among geographical regions and population groups. The prevalence of anti-HAV antibodies in the general population varies widely among countries. In Europe, the seroprevalence of HAV is reported to range from 32% to 88%. The aim of this study was to determine the seroprevalence of HAV among the general Croatian population. During a 2-year period (2008-2009), a total of 791 serum samples were tested for the presence of anti-HAV total (IgM+IgG) and anti-HAV IgM antibodies using an automated enzyme-linked fluorescent assay (Mini Vidas; bioMérieux, Marcy l'Etoile, France). The overall anti-HAV seroprevalence was 41.6%. The observed difference in the seroprevalence rates among male and female patients was not statistically significant (44% vs. 39.6%, P = 0.218). A marked increase in anti-HAV seropositivity with age was observed (P < 0.001). The seroprevalence did not differ significantly between participants residing in rural regions (45.3%) and those residing in urban regions (40.6%, P = 0.292). Our results corroborate those of seroprevalence studies in other developed countries. More than half of the Croatian population (59.4%) is susceptible to HAV infection. Older age is an important predictor for being anti-HAV positive.

Challenges to mapping the health risk of hepatitis A virus infection

BackgroundWorld maps are among the most effective ways to convey public health messages such as recommended vaccinations, but creating a useful and valid map requires careful deliberation. The changing epidemiology of hepatitis A virus (HAV) in many world regions heightens the need for up-to-date risk maps. HAV infection is usually asymptomatic in children, so low-income areas with high incidence rates usually have a low burden of disease. In higher-income areas, many adults remain susceptible to the virus and, if infected, often experience severe disease.ResultsSeveral challenges associated with presenting hepatitis A risk using maps were identified, including the need to decide whether prior infection or continued susceptibility more aptly indicates risk, whether to display incidence or prevalence, how to distinguish between different levels of risk, how to display changes in risk over time, how to present complex information to target audiences, and how to handle missing or obsolete data.ConclusionFor future maps to be comparable across place and time, we propose the use of the age at midpoint of population susceptibility as a standard indicator for the level of hepatitis A endemicity within a world region. We also call for the creation of an accessible active database for population-based age-specific HAV seroprevalence and incidence studies. Health risk maps for other conditions with rapidly changing epidemiology would benefit from similar strategies.

Seroprevalence of Hepatitis A among Thai Population Residing Near Myanmar Border

hen compared with Thailand, the seroprevalence of hepatitis A virus (HAV) is extremely high among its neighbouring countries. To investigate the seroprevalence of HAV among the Thai people residing in the border area between Thailand and Myanmar, 308 residents in Umphang, Maesod district, Tak, were recruited. Sera were tested for HAV IgG antibodies by enzyme-linked immunosorbent assay. The overall seroprevalence among the Thai people residing in the border area of Thailand was significantly higher than that among the general Thai population (71% vs 27% respectively, p < 0.05). As asymptomatic or mild HAV infection typically occurs in children, the Thai people residing in the border area may receive little benefit from universal HAV vaccination. Lower protective antibodies against HAV, along with the exclusion of HAV vaccine from the Expanded Programme on Immunization, potentially increase the susceptibility to HAV among the general Thai population and may lead to more future outbreaks if HAV is introduced from the border areas. The findings suggest that HAV vaccines should be recommended to travellers before their journey to the border between Thailand and Myanmar where HAV is endemic.

Determinants of anti-hepatitis A antibody seroprevalence in 2- to 19-year-olds in the USA using NHANES 2007–2008

SUMMARYThe aim of the study was to describe the epidemiology and determinants of anti-hepatitis A seroprevalence in 2- to 19-year-olds in the USA for 2007–2008. This study was conducted in a sample of 2621 individuals aged 2–19 years in the USA using data from National Health and Nutrition Examination Survey (NHANES) 2007–2008. The overall seroprevalence of anti- hepatitis A virus (HAV) in this population was 39% (95% confidence interval 32·6–45·3). HAV seroprevalence was higher in Mexican Americans than other ethnic groups, in younger persons, and in those who reported previous vaccination compared to those who did not. We concluded that anti-hepatitis A seroprevalence rates are increasing in younger individuals in the USA, indicating a shift of seroprevalence over time due to vaccination status. Findings are consistent with a persistent influx of infection through international travel and migration and highlight the need to discern hepatitis A infection from vaccination status when assessing the effectiveness of vaccination using seroprevalence data.

Seroprevalence of Hepatitis A and E Viruses Based on the Third Korea National Health and Nutrition Survey in Korea

ObjectivesThe purpose of this study was to investigate the seroprevalence of hepatitis A virus (HAV) and hepatitis E virus (HEV) in Korea during 2005. MethodsStudy subjects were selected from across Korea using a stratified multistage probability sampling design, and HAV and HEV seroprevalence was compared on the basis of sex, age, and residency. A total of 497 rural and urban people aged 10–99 years of age (mean ± SD age = 28.87 ± 17.63 years) were selected by two-stage cluster sampling and tested serologically for anti-HAV and anti-HEV IgG using an enzyme-linked immunosorbent assay. ResultsAmong this population, the overall seroprevalence of HAV was 63.80% (55.21% aged in their 20s and 95.92% in their 30s, p < 0.01) and that of HEV was 9.40% (5.21% aged in their 20s and 7.14% in their 30s, p < 0.01). Seroprevalence also varied according to area of residence. HEV prevalence in rural areas was higher than that of urban regions based on the anti-HEV antibody, odds ratio 3.22 (95% confidence interval: 1.46–7.10, p < 0.01). There were no significant differences between male and female against anti-HAV/HEV antibodies. ConclusionOur study suggested that the seropositive rates of HAV and HEV might be related to age and environmental conditions.

Seroprevalence of Hepatitis A and Associated Socioeconomic Factors in Young Healthy Korean Adults

An epidemiologic shift of hepatitis A virus (HAV) seroprevalence is expected due to an improvement in socioeconomic status in young adults in Korea. We investigated the age-specific seroprevalence and socioeconomic factors associated with HAV seropositivity in young, healthy Korean adults. Between March 2009 and February 2010, a total of 5,051 persons from 20 to 49 years of age presenting for a health check-up were included and responded to a questionaire. The seroprevalence of HAV was investigated by measuring immunoglobulin G (IgG) anti-HAV. A total of 984 pairs of cases and age- and sex-matched controls were analyzed for associated socioeconomic factors. The prevalence of seropositive HAV was 6.2% in the 20 to 29 age range, 33.1% in the 30 to 39 range and 82.4% in the 40 to 49 range (p<0.001). There were no significant differences in any group according to gender. A multivariate analysis for paired cases indicated that HAV seropositivity was significantly higher in the low monthly income (below five million won, approximately 4,300 dollars) group and the Helicobacter pylori (H. pylori)-positive group (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.27-2.14; p<0.001; OR, 1.45; 95% CI, 1.19-1.76; p<0.001, respectively). HAV seropositivity in young adults presenting for a health checkup appears to be decreasing, and the prevalence was significantly higher in the low monthly income group and the H. pylori-positive group.

Use of a Catalytic Model to Estimate Hepatitis A Incidence in a Low-Endemicity Country

Evaluating the cost-effectiveness of vaccine programs with dynamic modeling requires accurate estimates of incidence over time. Because infectious diseases are often underreported, supplementary data and statistical analyses are required to estimate true incidence. This study estimates the true incidence of hepatitis A virus (HAV) infection in Canada using a catalytic model. A catalytic model was used to reconcile HAV seroprevalence data with the corresponding true cumulative risk of infection estimated from incidence data. The average annual reported incidence was 6.2 cases per 100,000 from 1980 to 1989 and 7.7/100,000 from 1990 to 1999, indicating that Canada is a low-incidence country. The seroprevalence in Canadian-born individuals (n = 7 studies) was approximately 1%-8% in ages <20, 1%-11% in ages 20-29, 7%-29% in ages 30-39, and higher in older age groups. Between 1980 and 1995, the catalytic model estimated an average annual incidence of 60/100,000 (95% confidence interval, 33-524); approximately 7.73 (4.21-67.33) times the average annual reported incidence of 7.78/100,000. For a typical birth cohort of 403 434 Canadians born in 1990, the model predicted 32 750 HAV cases by age 39, with a corresponding seroprevalence of approximately 8.12% by the year 2029. Reliable estimates of true incidence of infectious disease are required for cost-effectiveness analysis of infectious disease programs. Catalytic models enable the synthesis of dispersed data, quantification of data limitations, and reconciliation of these limitations to estimate true incidence for economic evaluations.

Laboratory characteristics of recent hepatitis A in Korea: Ongoing epidemiological shift

To evaluate seroprevalence of hepatitis A virus (HAV) antibody and investigate demographic, clinical, and laboratory features of recent cases in Korea. For the evaluation of hepatitis A seroprevalence, we analyzed the data from 3127 subjects including, healthcare workers and patients who visited Konkuk University Hospital, a secondary referral center, from January to October 2009. The sera with positive IgM were excluded from seroprevalence data for total HAV antibody. We retrospectively reviewed the electronic medical records of 419 patients with HAV, who were diagnosed by the presence of serum IgM antibodies against HAV. All patients presented at Konkuk University Hospital between August 2005 and September 2008. Among 3127 sera tested, 1428 (45.7%) were positive for anti-HAV antibody. The seroprevalence was very low in teenagers or those in their twenties, increased in those in their thirties, and was > 90% in older patients. In children younger than 10 years, seroprevalence was increased again. Most patients with HAV hepatitis were in their twenties and thirties. The gamma-glutamyl transpeptidase increased with age and was significantly higher in patients older than 30 years. Indicators of severity, such as decreased albumin and increased bilirubin, were also more prominent in the older age group; however, the leukocyte count was higher and the frequency of leukopenia was lower in younger patients than in older adults. There has been an apparent epidemiological shift in HAV seroprevalence and a change in the peak age of HAV hepatitis. This study could provide baseline data of recent hepatitis A in Asia.

The epidemiology of hepatitis A virus infections in four Pacific Island nations, 1995–2008

Historically, hepatitis A virus (HAV) has been highly prevalent in developing countries, with most infections occurring during childhood, when they are likely to be asymptomatic. Shifts in the acquisition of infection from childhood to adulthood, when clinical hepatitis is more likely, may leave populations vulnerable to large outbreaks. We conducted cross-sectional serosurveys from 1995 to 2008 in four Pacific Island nations to determine the proportion of people previously infected with HAV by measuring antibodies to HAV (anti-HAV). In American Samoa, 0.0% of 4- to 6-year-olds (95% CI 0.0-3.7) were anti-HAV positive. In Chuuk, FSM, 8.6% of 2- to 6-year-olds (95% CI 5.7-11.5) were anti-HAV positive compared with 98.3% of individuals > or =16 years old (95% CI 96.6-100). In Pohnpei, FSM, 0.8% of 2- to 9-year-olds (95% CI 0.0-1.6) were anti-HAV positive compared with 95.1% of > or =16 year-olds (95% CI 92.2-98.0). In RMI, 85.7% (95% CI 81.9-89.5) of 4- to 9-year-olds were anti-HAV positive. In Palau, 0.7% of 7- to 8-year-olds were anti-HAV positive (95% CI 0.0-1.8). The low HAV seroprevalence among children in American Samoa, FSM and Palau may indicate a vulnerability to hepatitis A morbidity among these populations. These data will be useful for evaluating the need for hepatitis A surveillance and vaccination programs.

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.

Seroprevalence of Hepatitis A Infection in the Turkish Republic of Northern Cyprus

Aims: This study was conducted to determine the seroprevalence of hepatitis A virus (HAV) infection in the Turkish Republic of Northern Cyprus. Materials and Methods: A total of 660 unvaccinated persons 1 to 30 years old were selected for the study with cluster sampling. Information on sociodemographic characteristics was gathered for each participant and, in 641 of them, anti-HAV antibodies were assayed using an enzyme immune assay. Results: Anti-HAV prevalence in the Turkish population under the age of 30 in Northern Cyprus was 23.9%. For the age groups 1-5, 6-10 and 11-15 years, seroprevalence rates were relatively low (11.4, 9.4 and 12%, respectively). For age groups 16 years and over, HAV seroprevalence gradually increased with age, rising to 30.4% in 16 to 20 years and to 52.5% in 21 to 30 years of age. In addition to age, other variables significantly associated with HAV seroprevalence included low family income, family size, waste water sewage, and the education level of parents. Conclusions: Anti-HAV seroprevalence in the Turkish Republic of Northern Cyprus shows an intermediate prevalence. As well as expanding health education and improving sanitation, a hepatitis A universal mass vaccination program would be logical for the population.

Hepatitis A in Korea: Epidemiological Shift and Call for Vaccine Strategy

Objective: The number of adult hepatitis A cases has progressively been increasing during the last several years in Korea. The aim of the present study was to describe the recent clinical features of hepatitis A and the seroprevalence of hepatitis A virus (HAV), and to discuss HAV vaccine strategy in Korea. Methods: Retrospective analysis of clinical characteristics of hepatitis A from 109 patients consecutively enrolled at a community hospital between 2003 and 2006 as well as cross-sectional study of seroprevalence of HAV from 307 patients of hospital population group during the same period were performed. Results: Most hepatitis A cases were young adults in their twenties or thirties, and the severity of the disease was related to the age of patients. The seroprevalence of HAV was 62%, which was dependent on the age of patients. HAV seroepidemiology in Korea is rapidly changing and a growing number of young adults are susceptible to HAV infection. Conclusions: The clinical features and the epidemiological shift of HAV urge Korea, as well as other countries which are experiencing similar issues, to promote childhood vaccination and consider catch-up vaccination for adolescents and young adults.

Seroprevalence of Hepatitis A in Thai Army Medical Cadets and Nursing Students: A Reflection of Regional Risk Differences

A cross-sectional study of 432 army college students comprising 278 medical cadets and 154 nursing students, ages ranging from 15 to 26 years, was conducted in 2001 to determine the seroprevalence of hepatitis A virus (HAV) antibody. Serum specimens were tested for HAV antibody by a commercial enzyme immunoassay method. Anti-HAV was detected in 14.0%, 17.5%, and 15.3% of medical cadets, nursing students, and the total cohort, respectively. There was no statistically significant difference in seroprevalence between medical cadets and nursing students. Increasing prevalence of HAV correlated with increasing age. Significantly higher seroprevalence was detected in students from provinces outside of Bangkok compared to those who were from Bangkok (18.7% vs. 9.8%). The highest HAV seroprevalence was observed in subjects from the northeastern region of Thailand, suggesting that this region may be associated with greater risk for infection and should be the focus of preventive health strategies.

Anti-hepatitis A virus seroprevalence among patients with chronic viral liver disease in Korea

It is generally recommended that patients with chronic viral hepatitis should be vaccinated against hepatitis A virus (HAV) infection. We intended to evaluate the prevalence of IgG anti-HAV according to age in patients chronically infected with hepatitis B virus or hepatitis C virus in Korea. From June to October 2006, 303 patients (226 male, 77 female) with chronic hepatitis, liver cirrhosis, or hepatocellular carcinoma were recruited (mean age 50.8+/-14.4 years; range 16-84). The sera were tested for antibodies to HAV, and overall and age-specific seroprevalence of anti-HAV was assessed. Hepatitis B virus infection was the etiology of liver diseases in 267 patients (88.1%), with hepatitis C virus infection in 36 (11.9%). The distribution of clinical diagnosis was chronic hepatitis in 86 patients (28.4%), liver cirrhosis in 36 (11.9%), and hepatocellular carcinoma in 181 (57.9%). The patients were categorized by decade of age and the distribution was as follows: nine patients (2.5%) in their teens, 23 (6.2%) in their 20s, 36 (12.4%) in their 30s, 78 (25.7%) in their 40s, 72 (24.1%) in their 50s, and 85 (29%) >or=61 years. The overall seroprevalence of anti-HAV was 87.8% (266/303), and no difference was observed in sex (86.7 vs. 90.9%, P=0.42). The seroprevalence in each age group was 22.2, 26.1, 72.2, 97.4, 100 and 98.8%, respectively, showing marked increase in those over 40 years of age (P<0.001). Our study demonstrates that most Korean patients over 40 years of age with chronic liver disease have already been exposed to HAV.

Hepatitis A seroprevalence and its relationship with environmental factors in children of different age groups in Kahramanmaras, Eastern Mediterranean region of Turkey

Hepatitis A infections are influenced by environmental and socioeconomic factors. Epidemiologic studies regarding hepatitis A virus (HAV) infection in Turkey have not previously examined these factors. We investigated HAV seroprevalence and its association with sociodemographic factors among children of various ages in the Eastern Mediterranean region of Turkey. The study included 1142 children (603 male and 539 female) between ages of 6 months and 18 years. Seropositivity in the whole group was 57.2%. HAV prevalence rates according to age groups were as follows: 35.5% in 6-23 months group, 19.2% in 2-5 years group, 74.3% in 6-10 years group, 83.0% in 11-14 years group, 92.8% in 15-18 years group. Risk factors that influenced seropositivity were; dense population, over-crowded families, excessive number of siblings, low socioeconomic status and low education of the mother. As HAV seroprevalence in children older than 6 years of age is high, we recommend hepatitis A vaccination in this region after the first year of life.

Declining trend in the seroprevalence of infection with hepatitis A virus in Thailand

Since the mid 1970s, infection with hepatitis A virus (HAV) in Thailand has shifted from hyper-endemic to mesoendemic. In 2004, to explore this trend in prevalence further, 3997 subjects from four geographically distinct provinces of Thailand were tested, in a commercial ELISA, for antibodies to HAV. The results indicate that the seroprevalence of HAV continues to fall, almost certainly because the profound socio-economic development that has occurred over the last few decades in Thailand has brought with it significant improvements in sanitation and personal hygiene. As exposure to HAV declines, however, the risks of symptomatic and potentially severe infection in adulthood (rather than asymptomatic infection during childhood) and of epidemics of such infection, which would lead to profound economic loss, increases. Improvements in hygiene and sanitation to reduce exposure to the virus and measures to reduce the incidence of symptomatic disease in those infected, such as vaccination (which may only be cost-effective when targeted at high-risk groups), need to be carefully considered.

Hepatitis A seroepidemiology in Eastern Turkey

It has been reported that there are great deal of changes in the epidemiology of hepatitis A at the present. The epidemiologic studies regarding to hepatitis A virus (HAV) infection are not sufficient both in the country and study region. To investigate HAV seroprevalence and association with socio-demographic variables. Cross-sectional and community based study. Erzurum Province, Eastern Turkey between April and June 1998. Four hundred and fifty persons under the age of 30 years. The rate of the study involvement was 87.1% (392 persons) and ratio for seropositivity 84.2%. Although seropositivity is elevated by age, it has been high within the younger age group. Epidemiological changes could not be interpreted, since the study results were first for the group of people aged under 30 years. Statistical significance was found between hepatitis A seroprevalence and age, the number of households and localisation of toilet within the house. There was no correlation between hepatitis A and sex, jaundice history, family type, tap water availability in the residential area. The frequency of hepatitis A infection appearance in the region was found out to be high as compared to other regions of Turkey.

Hepatitis A vaccines and the elderly

Hepatitis A virus (HAV) exposure in unprotected adults may cause severe and serious symptoms, with risk of both morbidity and mortality increasing with age. As seroprevalence of HAV is low in industrialised countries, and an increasing number of people, with an increasing median age, travel from areas of low HAV endemicity to high endemicity, pre-travel vaccination is warranted. Vaccination of the elderly against HAV, however, may be associated with reduced seroprotection, since the immune response decreases with age. Studies with monovalent hepatitis A vaccine or combined hepatitis A and B vaccine show good efficacy in adults in general. Few studies have assessed the immune response in older adults. The only prospective study with monovalent hepatitis A vaccine in the elderly showed a reduced seroprotection of approximately 65% after a single primary dose in subjects over the age of 50 years, while seroprotection was 98% in this age group after receiving a booster dose. The only prospective study with combined hepatitis A and B vaccine in younger subjects or older than 40 years showed similar seroprotection (99-100%) against HAV compared to a monovalent vaccine after receiving three doses. As data on seroprotection for HAV in the elderly are limited, further studies are needed to elucidate how optimal protection in the elderly can be achieved. In the mean time, based on the available data, the suggestion is made to screen elderly travellers to areas endemic for HAV for the presence of naturally acquired immunity, and, if found susceptible, be immunised well in advance of their trip, to allow time for post-vaccination antibody testing and/or administration of a second dose of the vaccine.

HEPATITIS A IN LEBANON: A CHANGING EPIDEMIOLOGICAL PATTERN

In this multicenter study in Lebanon, hepatitis A virus (HAV) seroprevalence rates were surveyed by age, gender, and socioeconomic factors. Blood samples collected from 606 subjects aged 1 to 30 years were analyzed for anti-HAV IgG. Age was the most important factor influencing HAV seroprevalence. HAV seroprevalence rates in the current study were about 78% in the > or = 21 years age group, 28% in the 6-10 years age group, and 11% in the 1-5 years age group as compared with 97.7% in adults, 85% in children aged 6-12 years, and 40% in children aged 1 to 5 years in previous studies, demonstrating a shift in HAV seroprevalence from the younger to the higher age groups. In light of the severity of the disease in adults and availability of safe and effective vaccines against HAV infection, introduction of HAV vaccination into the national immunization schedule of Lebanon should be considered.

AGE-SPECIFIC SEROPREVALENCE OF HEPATITIS A AMONG SCHOOL CHILDREN IN CENTRAL TUNISIA

Hepatitis A virus (HAV) has different epidemiologic and clinical patterns, depending on the level of endemicity in a given geographic area. Tunisia is considered a region of high endemicity for hepatitis. Improvement of socioeconomic conditions in this country has made a determination of the seroprevalence of this disease advisable. We assessed the seroprevalence of HAV in Sousse in central Tunisia. A total of 2,400 school children 5-20 years of age (mean +/- SD age = 11.7 +/- 3.5 years) were selected by two-stage cluster sampling and tested serologically for IgG antibody to HAV by using an enzyme-linked immunosorbent assay. The overall seroprevalence among this population was 60% (44%, in children < 10 years old, 58% in those 10-15 years of age, and 83% in those > 15 years of age. Seroprevalence also varied according to area of residence. At the age of 10, 21.3% of school children living in the urban areas and 87.7% of those living in rural areas had antibodies to HAV. Other factors that increased seroprevalence included non-potable water, crowding, and a low education level of parents with odds ratios of 4.37, 2.96, and 2.62, respectively. This study has shown an increase of seroprevalence with age, suggesting that transmission among younger children has decreased, particularly in urban areas. Programs to prevent hepatitis A may need to be modified based upon the changing age distribution of the disease and mass vaccination program could be indicated if additional incidence and prevalence data confirm the intermediate endemicity of HAV.