Seroepidemiology of hepatitis A and hepatitis B virus in Luxembourg

A prospective seroepidemiological survey was carried out in Luxembourg in 2000-2001 to determine the antibody status of the Luxembourg population against hepatitis A virus (HAV) and hepatitis B virus (HBV). One of the objectives of this survey was to assess the impact of the hepatitis B vaccination programme, which started in May 1996 and included a catch-up campaign for all adolescents aged 12-15 years. Venous blood from 2679 individuals was screened for the presence of antibodies to HAV antigen and antibodies to hepatitis B surface antigen (anti-HBs) using an enzyme immunoassay. Samples positive for anti-HBs were tested for antibody to hepatitis B core antigen (anti-HBc) using a chemiluminiscent microparticle immunoassay to distinguish between individuals with past exposure to vaccine or natural infection. The estimated age-standardized anti-HAV seroprevalence was 42.0% [95% confidence interval (CI) 39.8-44.1] in the population >4 years of age. Seroprevalence was age-dependent and highest in adult immigrants from Portugal and the former Yugoslavia. The age-standardized prevalence of anti-HBs and anti-HBc was estimated at 19.7% (95% CI 18.1-21.3) and 3.16% (95% CI 2.2-4.1) respectively. Anti-HBs seroprevalence exceeding 50% was found in the cohorts targeted by the routine hepatitis B vaccination programme, which started in 1996. Our study illustrates that most young people in Luxembourg are susceptible to HAV infection and that the hepatitis B vaccination programme is having a substantial impact on population immunity in children and teenagers.     

Cost analysis of two strategies for preventing hepatitis A virus infection in Spanish travellers to developing countries.

Our objectives were to assess the prevalence of anti-hepatitis A (HAV) antibodies in Spanish travellers to developing countries and to carry out a cost analysis to allow the comparison of two vaccination strategies. Adult subjects were selected from among travellers to developing countries. Information was obtained on age, sex, destination, previous vaccination against HAV and having received immunoglobulin. Blood specimens were obtained for anti-HAV antibody determination. A total of 485 travellers were studied. The prevalence of anti-HAV antibody was 30.5% (95% CI 26-35). Antibody prevalence was inversely correlated with age: 9.8% in 18-25 years of age, rising to 75.4% in those 41-55 years of age. Cost analysis determined that the critical value of prevalence for vaccination with HAV vaccine was 37.5%. It was concluded that the youngest Spanish travellers lack anti-HAV antibodies. Vaccination without screening in those < or = 35 years of age and screening before vaccination for those > 35 years, are the preferred alternatives.     

Lack of evidence for increased risk of hepatitis A infection in homosexual men.

In 1997, prevalence of and risk factors for hepatitis A virus (HAV) infection were evaluated in 146 homosexual and 286 heterosexual men attending a Sexually Transmitted Disease (STD) Clinic in Rome, Italy. Total HAV antibody (anti-HAV) was detected in 60.3% of homosexuals and 62.2% of heterosexuals. After adjustment for the confounding effects of age, years of schooling, number of sexual partners, use of condoms, and history of STD, homosexuals were not found to be at increased risk of previous HAV exposure than heterosexuals (OR 1.1; 95% CI 0.7-1.9). Independent predictors of the likelihood of anti-HAV seropositivity among homosexuals and heterosexuals were: age older than 35 years and positive syphilis serology which is likely a proxy of lifestyles that increase the risk of faecal-oral infections. These findings do not support a higher risk in homosexual men but could suggest a role for the vaccination of susceptible patients attending STD clinics.     

Cost analysis of two strategies for hepatitis A vaccination of hospital health-care personnel in an intermediate endemicity area.

The aim of the study was to carry out a cost analysis to allow the comparison of the cost of two vaccination strategies against Hepatitis A in health-care personnel. A total of 423 health-care workers were recruited at one General Hospital of Madrid, Spain. Blood specimens were obtained for anti-HAV antibody determination. The prevalence of anti-HAV antibody was 40% (95% CI: 35-45) and it was directly correlated with age. Cost analysis determined that the critical value of prevalence for vaccination with HAV vaccine was 23%. In hospital health-care workers < or =30 years in age, vaccination with HAV vaccine (without screening) would be the less costly strategy. In those >30 years in age, it would be less costly to screen for anti-HAV antibody first and vaccinate those who are antibody-negative.     

Seroprevalence and risk factors for hepatitis A among Montreal street youth

OBJECTIVE: To estimate the prevalence of hepatitis A virus (HAV) antibodies among Montreal street youth. METHOD: Anti-HAV antibody testing was performed on blood samples from a hepatitis B and C study conducted among street youth in 1995-96. RESULTS: Among the 427 youth aged 14 to 25 years, prevalence of HAV antibodies was 4.7% (95% confidence interval [CI]: 2.9%-7.2%). A multivariate logistic regression analysis showed that birth in a country with a high anti-HAV prevalence (Adjusted odds ratio [AOR]: 200.7; 95% CI: 38.1-1058.4), having had sexual partner(s) with history of unspecified hepatitis (AOR: 13.8; 95% CI: 4.2-45.2), and insertive anal penetration (AOR: 5.1; 95% CI: 1.6-16.7) were independently associated with infection. CONCLUSION: Based on the relatively low HAV prevalence, the high prevalence of risk factors for infection, and the substantial hepatitis B and C prevalence, vaccination against hepatitis A is now actively promoted among Montreal street youth.     

The seroepidemiology of hepatitis A and B in a Japanese town.

Sera collected from 1,118 healthy children and adults aged between four years and 90 years during the period 1989 to 1990, were tested for serological markers of hepatitis A virus (HAV) [antibody to HAV (anti-HAV)] and hepatitis B virus (HBV) [hepatitis B surface antigen (HBsAg) and antibody to hepatitis B surface antigen (anti-HBsAb)]. The overall prevalence rates of anti-HAV, HBsAg, and anti-HBV were 20.2%, 0.36%, and 5.1%, respectively. No body was found to be positive for anti-HAV below 30 years of age but more than 70% of the adults aged 50 years or over were positive for anti-HAV. The level of exposure of HAV infection is declining in Japan and paradoxically at the same time a vast majority of people are becoming susceptible to more severe illness. The fall in prevalence of HBsAg possibly represents the positive impact of ongoing vaccination programs and other preventive measures against HBV.     

Decreasing immunity to hepatitis A virus infection among US adults: Findings from the National Health and Nutrition Examination Survey (NHANES), 1999–2012

BackgroundThe clinical course of hepatitis A virus (HAV) infection is more severe with increased age. In the United States, surveillance data reported to CDC since 2011 indicate increases in both the absolute number of cases and the mean age of cases. Total antibody to HAV (anti-HAV) is a marker of immunity.MethodsWe analyzed National Health and Nutrition Examination Survey (NHANES) data for anti-HAV from respondents aged ≥2 years collected from 2007 to 2012 and compared with data collected 10 years earlier (1999–2006). For US-born adults aged ≥20 years, we estimated age-adjusted anti-HAV prevalence by demographic and other characteristics, evaluated factors associated with anti-HAV positivity and examined anti-HAV prevalence by decade of birth.ResultsThe prevalence of anti-HAV among adults aged ≥20 years was 24.2% (95% CI 22.5–25.9) during 2007–2012, a significant decline from 29.5% (95% CI 28.0–31.1) during 1999–2006. Prevalence of anti-HAV was consistently lower in 2007–2012 compared to 1999–2006 by all characteristics examined. In 2007–2012, the lowest age-specific prevalence was among adults aged 30–49 years (16.1–17.6%). Factors significantly associated with anti-HAV positivity among adults were older age, Mexican American ethnicity, living below poverty, less education, and not having insurance. By decade of birth, the prevalence of anti-HAV was slightly lower in 2009–2012 than in 1999–2002, except among persons born from 1980 to 1989.ConclusionsNHANES data document very low prevalence of hepatitis A immunity among U.S. adults aged 30–49 years; waning of anti-HAV over time may be minimal. Improving vaccination coverage among susceptible adults should be considered.     

Age-specific seroprevalence of hepatitis A infection among children visited in pediatric hospitals of Tehran, Iran

BACKGROUND: Hepatitis A is an enterically transmitted disease that still remains endemic in many developing countries. In some countries improvements in living conditions have recently led to changing in epidemiology of hepatitis A virus (HAV) infection. In our country there are very few reports on prevalence of HAV infection. OBJECTIVE: To determine the seroprevalence of anti-HAV IgG among children visited in pediatric hospitals of Tehran, Iran. METHODS: The study group included 1018 children who were 6 months-14.9 years of age. These children were visited in four major pediatric hospitals of Tehran. The children were separated to three age groups: Group 1 (6 months-4.9 years; n = 469), Group 2 (5.0-9.9 years; n = 290), and Group 3 (10.0-14.9 years; n = 259). Serum anti-HAV IgG was tested with commercial ELISA kits. The data were tested for statistical significance with chi2 test. RESULTS: In all subjects, seroprevalence of hepatitis A was 22.3% (95% CI: 19.7, 24.9). There was no significant difference between genders (22.2% vs. 22.5% in males and females, respectively) and among age groups (Group I was 22.1% and Group 3 was 25.9; p > 0.05). CONCLUSIONS: In summary, it seems that HAV infection is not highly endemic at least in some urban areas of Iran. On the basis of this epidemiologic data, post exposure prophylaxis would be necessary for children and young adults, and hepatitis A vaccination strategy should be revised.     

Self-reported hepatitis A vaccination as a predictor of hepatitis A virus antibody protection in U.S. adults: National Health and Nutrition Examination Survey 2007–2012

ObjectivesTo estimate the predictive value of self-reported hepatitis A vaccine (HepA) receipt for the presence of hepatitis A virus (HAV) antibody (anti-HAV) from either past infection or vaccination, as an indicator of HAV protection.MethodsUsing 2007–2012 National Health and Nutrition Examination Survey data, we assigned participants to 4 groups based on self-reported HepA receipt and anti-HAV results. We compared characteristics across groups and calculated three measures of agreement between self-report and serologic status (anti-HAV): percentage concordance, and positive (PPV) and negative (NPV) predictive values. Using logistic regression we investigated factors associated with agreement between self-reported vaccination status and serological results.ResultsDemographic and other characteristics varied significantly across the 4 groups. Overall agreement between self-reported HepA receipt and serological results was 63.6% (95% confidence interval [CI] 61.9–65.2); PPV and NPV of self-reported vaccination status for serological result were 47.0% (95% CI 44.2–49.8) and 69.4% (95% CI 67.0–71.8), respectively. Mexican American and foreign-born adults had the highest PPVs (71.5% [95% CI 65.9–76.5], and 75.8% [95% CI 71.4–79.7]) and the lowest NPVs (21.8% [95% CI 18.5–25.4], and 20.0% [95% CI 17.2–23.1]), respectively. Young (ages 20–29 years), US-born, and non-Hispanic White adults had the lowest PPVs (37.9% [95% CI 34.5–41.5], 39.1% [95% CI, 36.0–42.3], and 39.8% [36.1–43.7]), and the highest NPVs (76.9% [95% CI 72.2–81.0, 78.5% [95% CI 76.5–80.4)], and 80.6% [95% CI 78.2–82.8), respectively. Multivariate logistic analyses found age, race/ethnicity, education, place of birth and income to be significantly associated with agreement between self-reported vaccination status and serological results.ConclusionsWhen assessing hepatitis A protection, self-report of not having received HepA was most likely to identify persons at risk for hepatitis A infection (no anti-HAV) among young, US-born and non-Hispanic White adults, and self-report of HepA receipt was least likely to be reliable among adults with the same characteristics.     

Are homosexual males a risk group for hepatitis A infection in intermediate endemicity areas?

The purpose of this study was to examine the prevalence of antibody against hepatitis A (anti-HAV) in a population of homosexual men compared with that of heterosexual men in an area of intermediate HAV endemicity (Madrid, Spain). A total of 148 patients were recruited in a Sexually Transmitted Diseases Clinic: 74 homosexuals (mean age of 28 +/- 5 years) and 74 heterosexuals (29 +/- 5 years). The prevalence of anti-HAV antibody was 47% and 43% for homo- and heterosexuals, respectively. Among the factors evaluated (age, sexual orientation and practices, travel to high HAV endemicity areas) oral-anal contact was significantly associated with a higher prevalence of anti-HAV antibody (odds ratio, 2.8; 95% confidence interval, 1.1-7.4; P = 0.03). These results indicated that in an area of intermediate endemicity young homosexual men are not at increased risk of having acquired hepatitis A infection than heterosexuals. Oral-anal contact is an independent risk factor that influences the presence of anti-HAV antibody, regardless of sexual orientation.     

Antibodies to hepatitis A virus in Italian patients with chronic liver disease.

To improve our knowledge for future hepatitis A virus (HAV) vaccination strategies we carried out a multicentre study on naturally acquired immunological protection against HAV in patients with chronic hepatitis in Italy. We enrolled 830 consecutive patients with chronic hepatitis on their first observation at one of the six Italian liver units participating in the study. Six hundred and fifty-eight patients (79.3%) were positive for total anti-HAV and 172 (20.7%) were negative. The anti-HAV negative patients were younger (median age 33, range 11-78) than the anti-HAV positive (median age 56, 18-87). There was a higher prevalence of cases with circulating anti-HAV among the 508 patients residing in southern Italy than in the 322 residing in northern Italy (88.8% vs. 64%, P < 0.001). No significant difference in the anti-HAV prevalence was observed between patients from northern Italy and those from southern Italy aged 0-30 years or in those over 60 years, while in those 31-60 years old there was a higher prevalence of anti-HAV positive patients from southern Italy (90.2% vs. 65.8%, P < 0.0001). Of the patients with liver cirrhosis in this study, only 3 of the 26 (11.5%) from northern Italy and 8 of the 228 (3.5%) from southern Italy had no immunological protection against HAV infection. The data suggest that the number of patients with chronic liver disease without naturally acquired immunity against HAV is substantial in Italy, particularly in the north of the country, and that new vaccination strategies are needed.     

Hepatitis A shifting epidemiology in South-East Asia and China

A review of the epidemiology of hepatitis A virus (HAV) infection over the last 20 years shows shifting patterns in the prevalence of antibodies to HAV (anti-HAV) throughout South-East Asia and China. A number of countries have shifted from high to moderate and from moderate to low endemicity, with a corresponding increase in the age of exposure from childhood to early adulthood. The changes have resulted from improvements in hygiene, sanitation and the quality of drinking water, reflecting improvements in living standards and socioeconomic progress. In general in the late 1970s and early 1980s, 85-95% of the population of developing countries like the Philippines, Korea, China and Thailand were anti-HAV-positive by age 10-15 years, compared with only about 50% in the more affluent countries like Malaysia and Singapore. In the early 1990s, 85-95% of the population were immune by age 30-40 years in the Philippines, Korea, China and Thailand, and by 50 years of age and above in Malaysia and Singapore. Similar trends were noted in Hong Kong, Taiwan and Japan. Exposure to HAV at a later age may be associated with an increase in hepatitis A morbidity and a greater propensity for outbreaks.     

Hepatitis A infection: A seroepidemiological study in young adults in North-East Italy

During the period from January to May 1994, the prevalence of antibodies to hepatitis A virus infection (anti-HAV) was tested by immunoenzyme assay in the serum samples of 620 apparently healthy subjects (81% males, 19% females), from 10 to 29 years old, resident in North-East Italy (Pordenone and surrounding district). The overall prevalence of anti-HAV was 3.7%. There was a significant lower prevalence in the group aged 10-19 than in the one aged 20–29 years (0.7% vs 6%; p < 0.001). Moreover, a significant sex difference was observed for the 20–29 year age group (p < 0.001). Among the various risk factors considered, family size and travelling abroad to endemic areas were significantly associated with HAV infection. Since a valid and effective vaccine against HAV infection has recently become available, anti-HAV vaccination campaigns can feasibly be programmed. However, different geographical regions present different epidemiological situations, so its use should be adapted to each region, with special attention to the cost-effectiveness of the immunisation programme. Our data suggest that in our region such vaccination could initially be proposed to high-risk subjects such as those travelling to endemic areas.     

Hepatitis A virus infection in the United States: serologic results from the Third National Health and Nutrition Examination Survey

To determine the prevalence of hepatitis A virus (HAV) infection in the general U.S. population, sera from participants in the Third National Health and Nutrition Examination Survey (NHANES III) conducted in 1988–1994 were tested for antibody to HAV (anti-HAV). Among 21,260 participants aged ≥6 years tested, the overall prevalence of infection was 31.3%, and increased markedly with age. The age-adjusted prevalence was significantly higher among foreign- compared to U.S.-born participants, and was highest among Mexican-Americans and lowest among non-Hispanic whites. Among U.S.-born children, only Mexican-American ethnicity and income below the poverty level were associated with HAV infection in a multivariate model. During this period before hepatitis A vaccination, age, ethnicity and birthplace were the most important determinants of HAV infection in the United States.     

Evaluation of occupational transmission of hepatitis A virus among wastewater workers

To provide information concerning potential occupational transmission of hepatitis A virus (HAV) among wastewater workers in a large city in the United States, a cross-sectional survey was performed using a saliva test to detect antibodies to HAV (anti-HAV). Fifty-nine (20%) of 302 participants tested positive for anti-HAV. After controlling for the confounding effects of age and race, wastewater work was not significantly associated with an increase in the prevalence of anti-HAV (prevalence ratio = 1.3; 95% confidence interval 0.7 to 2.4). Additionally, when examining only the wastewater workers, no statistically significant occupational risk factors for anti-HAV were identified. The results of this survey are consistent with the position of the Centers for Disease Control and Prevention regarding groups at risk for HAV infection.     

Changing epidemiology of hepatitis A infection in Izmir, Turkey

The seroprevalence study was conducted in order to determine the current seroepidemiology hepatitis A in Izmir, Turkey and to evaluate the epidemiological shift in HAV serostatus. Blood samples collected from 595 subjects aged 1-60 years were analyzed for anti-HAV IgG antibodies. The current study results were compared with those of a previous study conducted in 1998 involving the same location. There was a marked decrease in the prevalence of anti-HAV between 1998 and 2008. While anti-HAV seroprevalence rates in the current study were 4.6% in children aged 1-4 years, 23% in children aged 10-14 years, and 85% in young adults aged 20-29 years, the prevalence rates were 36% in the 1-4 years age group, 65% in the 10-14 years age group, and 95% in young adults in the previous study, indicating a shift in HAV seroprevalence from the younger to the higher age groups. As HAV infection in childhood is decreasing, the pool of susceptible adolescents and young adults is increasing in Izmir, Turkey. The majority of adolescent population is susceptible to HAV infection. The potential risk of HAV epidemics still exists. The situation of Turkey, suggested to need for mass immunization. Also, introduction of hepatitis A vaccination into the national immunization schedule of Turkey should be considered.     

Prevalence of antibody to hepatitis A and hepatitis B viruses in selected populations of the South Pacific.

Five island populations representing the three major cultural groups of the South Pacific--Polynesia, Micronesia, Melanesia--were studied for prevalence of antibody to hepatitis A virus (anti-HAV) and of antibody to the core antigen of hepatitis B virus (anti-HBc). Sera were collected in the late 1950s and early 1960s, selected where possible for appropriate age and sex distributions, and were tested by radioimmunoassay. Rather marked differences in prevalence were observed. Anti-HBc patterns confirmed that HBV is endemic in the Pacific populations. Furthermore, the patterns differed somewhat from each other and did not correlate with ethnogeographic area. Prevalence of anti-HAV was high in all populations studied. A Unique pattern was found for the island of Ponape (Micronesia): In a Ponape population bled in 1963, anti-HAV was not detected in any individual under 20 years of age, but almost all individuals over that age were found to be seropositive. On testing a second group of sera collected in 1975, all individuals aged 14--21 years were found to be antibody positive, indicating that HAV had returned to Ponape sometime prior to 1975. There was no significant difference in the prevalence of HAV or HBV infection between males and females in any of the populations studied.     

高流行区甲型肝炎疫苗免疫方案研究

目的探讨甲型肝炎高流行区疫苗免疫方案。方法观察新生儿母传抗ＨＡＶ抗体的衰减及处于甲型肝炎流行不同阶段儿童甲型肝炎病毒感染率随年龄上升的规律。结果新生儿母传抗体的阳性率按ｌｏｇｉｓｔｉｃ曲线下降,１３个月内从９７．４％下降为５．０％;非流行期儿童甲型肝炎病毒感染率从１．５岁起随年龄上升,２岁前保持在１０％以内;流行期儿童甲型肝炎病毒感染率随年龄增加而起点提前,速度加快。鉴于甲型肝炎发病随年龄上升的起点滞后于感染,认为甲型肝炎高流行区新生儿甲型肝炎母传抗体向自然感染抗体转换的“窗口期”是在出生后１２～２４个月。结论根据流行情况与经济条件,儿童适宜的甲型肝炎疫苗免疫时机一般选择在１２～２４月龄     

A ten year serological survey of hepatitis A, B and C viruses infections in Nepal

BACKGROUND: In 1987, we reported that the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection in Nepal was low, as compared to hepatitis A virus (HAV) infection, and that no human T-lymphotropic type-1 (HTLV-1) infection was found in Nepal. OBJECTIVES: To determine changes in the prevalence of HAV, HBV, and HCV infections between 1987 and 1996 in inhabitants of Bhadrakali (suburban) and Kotyang (rural) villages in Nepal. STUDY DESIGN: We did a cross-sectional survey of 458 inhabitants of two Nepalese villages, to assess the prevalence of antibody to HAV (anti-HAV), antibody to hepatitis B core antigen (anti-HBc), hepatitis B surface antigen (HBsAg), antibody to HCV (anti-HCV), and antibody to HTLV-I (anti-HTLV-I). RESULTS: Anti-HAV was detected in 454 (99.1%), HBsAg in 5 (1.1%), anti-HBc in 33 (7.2%) and anti-HCV in 8 (1.7%) of serum samples tested in 1996. Statistically significant differences by gender or age group were nil. The prevalence of HCV infection was significantly higher in 1996 than in 1987 after adjusting for age of subjects living in the two villages (p < 0.01). The prevalence of HBsAg was significantly higher in 1996 than 1987 in Bhadrakali after adjusting for the factor of age (p < 0.05). Between 1987 and 1996, evidence for HTLV-1 positive residents was nil. CONCLUSION: These results suggest that HAV has been endemic in Nepal for long time while not of HBV, and that HCV infection tends to be increased recently.     

Participant-collected, mail-delivered oral fluid specimens can replace traditional serosurveys: a demonstration-of-feasibility survey of hepatitis A virus-specific antibodies in adults

BACKGROUND: Although population-based serosurveys offer an optimal measure of cumulative infection rates, they are seldom performed due to high cost and complex logistics. Use of participant self-collected oral fluid as a diagnostic specimen and mail for specimen delivery has the potential of generating reliable, population-representative data at limited cost. METHODS: A survey of oral fluid HAV-specific immunoglobulin G (an indicator of past HAV infection) was undertaken in a provincially representative sample of 20-39 year olds as a pilot study. A provincial administrative database served as the sampling frame. Potential participants were invited by mail to collect oral fluid and complete a questionnaire at home and return both by mail. Additional telephone prompting was directed at slow responders. Oral fluid was tested using a validated ELISA. RESULTS: From among 2,448 potential participants, contact by mail or telephone was made with 1,009 eligible subjects; 59% (585) participated. Materials withstood mailing and the quality of self-collected specimens was excellent. A positive test result was found in 22.1% overall and in 15.7% of self-reported non-vaccinated subjects. Among Canadian-born, non-vaccinated individuals, the positive test rate increased progressively from 1.2% (95% CI: 0-6.3) in 20-24 year olds to 16.4% (95% CI: 9.5-23.3) in 35-39 year olds. Antibody prevalence was higher among Canadian-born non-immunized 20-29 year olds who reported travel to developing countries (33.3%, 95% CI: 11.6-55.1) than in non-travellers (2.5%, 95% CI: 0.7-6.2). CONCLUSIONS: Mail-based population surveys of infection markers in oral fluid are feasible provided an appropriate sampling frame is used. This survey revealed a high anti-HAV antibody prevalence in young Canadian adults, increasing with age and travel to developing countries.