Initial evaluation of universal immunization with a single dose against hepatitis A virus in Central Brazil

ABSTRACT Vaccination against the hepatitis A virus (HAV) administered in two doses has been used effectively in universal child immunization programs in several countries. A single-dose vaccination was adopted in some low-income countries in an attempt to reduce costs without losing effectiveness. In 2014, single-dose universal vaccination was introduced in Brazil for children aged two years. Since such strategy is still not universally accepted, its efficacy should be compared to the two-dose strategy. To assess the humoral response after the single-dose HAV vaccination schedule, a cross-sectional study was conducted in Primavera do Leste, in Mato Grosso state, Central Brazil, including 265 children vaccinated through the National Immunization Program. Blood was collected by using a digital puncture and further applied to filter paper cards. Anti-HAV was detected in 218 out of 265 dried blood spots (DBS). Blood venous samples were collected from 34 out of 47 children who were not anti-HAV positive in DBS samples. Eighteen of them tested positive for anti-HAV, giving a final score of 93.6% (236/252) of seropositivity. In conclusion, this study demonstrated a high rate of anti-HAV positivity in the short term after single-dose hepatitis A vaccination in the population investigated. Moreover, the DBS was shown to be a reliable tool for detecting anti-HAV antibodies.

Hepatitis A seroprevalence in public school children in Campos dos Goytacazes, Rio de Janeiro State, Brazil, prior to the introduction of the hepatitis A universal childhood vaccination / Soroprevalência da hepatite A em crianças de escolas públicas em Campos dos Goytacazes, Rio de Janeiro, Brasil, antes da introdução da vacinação infantil universal / Seroprevalencia de la hepatitis A en niños de escuelas públicas en Campos dos Goytacazes, Río de Janeiro, Brasil, antes de la introducción de la vacunación infantil universal

Abstract: This cross-sectional study was carried out between August 2011 and July 2012 in the city of Campos dos Goytacazes in Rio de Janeiro State, Brazil. Dried blood spot samples were collected on filter paper from 919 individuals between the ages of 1 and 19 and were tested for antibodies against the hepatitis A virus (anti-HAV). The total prevalence was 20.7%, while 94.7% of children under the age of 5 were found to be susceptible to HAV infection. The prevalence of anti-HAV increased with age, reaching 33.3% among individuals aged between 15 and 19, thereby indicating that this municipality has a low level of endemicity for hepatitis A. Age, non-white skin color, accustomed to swimming in the river and more than five people living at home were the factors that were associated with an increase in the chance of a positive anti-HAV result. Mother's education level (secondary or tertiary) was considered a protective factor for HAV infection. The data obtained showed that a large proportion of the children from Campos dos Goytacazes were at risk of HAV infection, which should be minimized with the introduction of the vaccination program against hepatitis A that was launched in the municipality in 2011.

Resumo: Estudo do corte transversal, realizado entre agosto de 2011 e julho de 2012 em Campos dos Goytacazes, Rio de Janeiro, Brasil. Amostras de sangue capilar em papel de filtro foram coletadas de 919 indivíduos com idade entre 1 e 19 anos e testadas para anticorpos para o vírus da hepatite A (anti-HAV). A prevalência total foi de 20,7% e 94,7% das crianças abaixo de 5 anos foi suscetível a infecção pelo HAV. A prevalência de anti-HAV aumentou com a idade, alcançando 33,3% entre indivíduos com 15 a 19 anos, caracterizando este município com um nível baixo de endemicidade para hepatite A. Idade, cor da pele não-branca, hábito de nadar no rio e número de moradores na residência acima de 5 foram associados com o aumento de chance de ser positivo para anti-HAV. O nível educacional materno (médio ou superior) foi considerado como fator de proteção para a infecção pelo HAV. Os dados obtidos mostraram que uma grande parte das crianças de Campos dos Goytacazes estava sob risco de infecção pelo HAV, o que deve ser minimizado com o programa de vacinação contra hepatite A implantado em 2011 no município.

Resumen: Estudio de corte transversal, realizado entre agosto de 2011 y julio de 2012 en Campos dos Goytacazes, Río de Janeiro, Brasil. Se recogieron muestras de sangre capilar en papel de filtro de 919 individuos con una edad entre 1 y 19 años y testadas para anticuerpos del virus de la hepatitis A (anti-HAV). La prevalencia total fue de un 20,7% y un 94,7% de los niños por debajo de los 5 años fue susceptible a la infección por el HAV. La prevalencia de anti-HAV aumentó con la edad, alcanzando un 33,3% entre individuos con 15 a 19 años, caracterizando este municipio con un nivel bajo de endemicidad para la hepatitis A. Edad, color de piel no-blanca, hábito de nadar en el río y un número de ocupantes en la residencia de más de 5 se asociaron con el aumento de oportunidad de ser positivo para anti-HAV. El nivel educacional materno (medio o superior) se consideró como un factor de protección para la infección por el HAV. Los datos obtenidos mostraron que una gran parte de los niños de Campos dos Goytacazes estaba bajo riesgo de infección por el HAV, lo que debe ser minimizado con el programa de vacunación contra la hepatitis A implantado en 2011 en el municipio.

SEROLOGICAL DETECTION OF HEPATITIS A VIRUS IN FREE-RANGING NEOTROPICAL PRIMATES (Sapajus spp., Alouatta caraya) FROM THE PARANÁ RIVER BASIN, BRAZIL

Nonhuman primates are considered as the natural hosts of Hepatitis A virus (HAV), as well as other pathogens, and can serve as natural sentinels to investigate epizootics and endemic diseases that are of public health importance. During this study, blood samples were collected from 112 Neotropical primates (NTPs) (Sapajus nigritus and S. cay, n = 75; Alouatta caraya, n = 37) trap-captured at the Paraná River basin, Brazil, located between the States of Paraná and Mato Grosso do Sul. Anti-HAV IgG antibodies were detected in 4.5% (5/112) of NTPs, specifically in 6.7% (5/75) of Sapajus spp. and 0% (0/37) of A. caraya. In addition, all samples were negative for the presence of IgM anti-HAV antibodies. These results suggest that free-ranging NTPs were exposed to HAV within the geographical regions evaluated.

Reappraisal of the Immunogenicity and Safety of Three Hepatitis A Vaccines in Adolescents

Although the overall incidence of hepatitis A in Korea has been decreasing, adolescents remain highly vulnerable to its outbreaks. This study was conducted to compare the immunogenicity and safety of three hepatitis A vaccines in Korean adolescents. Healthy anti-hepatitis A virus seronegative subjects aged 13 to 19 yr were randomized in three equal groups to receive two doses of Avaxim(TM), Epaxal(R), or Havrix(R), 6 to 12 months apart. Seroconversion rates one month after the first dose were 98%, 95%, and 93% for Avaxim(TM), Epaxal(R), and Havrix(R), respectively. Seroconversion rates reached 100% for all vaccine groups one month after the second dose. Anti-HAV geometric mean concentrations (GMCs) were 7,207.7 mIU/mL (95% CI, 6023.1-8684.7), 1,750.5 mIU/mL (95% CI, 1362.9-2248.3), and 1,953.5 mIU/mL (95% CI, 1459.4-2614.7) after two doses of Avaxim(TM), Epaxal(R), and Havrix(R) respectively. Avaxim(TM) was significantly more immunogenic than Epaxal(R) and Havrix(R), whereas there were no significant differences in antibody responses between Epaxal(R) and Havrix(R). Local and systemic solicited adverse events (AEs) were mostly of mild-to-moderate intensity and resolved within 5 days. No serious AEs were reported. In conclusion, all three vaccines are highly immunogenic and well-tolerated in Korean adolescents. (Clinical Trial Registry NCT00483470)

Risk Factors for Acute Hepatitis A Infection in Korea in 2007 and 2009: A Case-Control Study

This study aimed to identify the risk factors associated with acute hepatitis A virus (HAV) infection in the Korean population. Participants were recruited from five referral hospitals across the country in 2007 and from 11 hospitals in 2009. Patients with positive anti-HAV IgM antibody tests became the case group, while patients treated for non-contagious diseases at the same hospitals were recruited as controls. A total of 222 and 548 case-control pairs were studied in the 2007 and 2009 surveys, respectively. Data from the surveys were analyzed jointly. In a multivariate analysis, sharing the household with HAV-infected family members (OR, 6.32; 95% CI, 1.4-29.6), contact with other HAV-infected individuals (OR, 4.73; 95% CI, 2.4-9.4), overseas travel in 2007 (OR, 19.93; 95% CI, 2.3-174.4), consumption of raw shellfish (OR, 2.51; 95% CI, 1.8-3.5), drinking bottled water (OR, 1.64; 95% CI, 1.3-8.4), and occupation that involve handling food (OR, 3.30; 95% CI, 1.3-8.4) increased the risk of HAV infection. Avoiding contact with HAV-infected individuals and avoiding raw foods eating could help minimize the risk of hepatitis A infection. Immunization must be beneficial to individuals who handle food ingredients occupationally or travel overseas to HAV-endemic areas.

An immunoenzymatic assay for the diagnosis of hepatitis A utilising immunoglobulin Y

The detection of anti-hepatitis A virus (HAV) antibody levels by diagnostic kits in the convalescent period of disease generally use immunoglobulin G (IgG), which is expensive. An alternative to IgG is immunoglobulin Y (IgY), an immunoglobulin antibody encountered in birds and reptiles. The aim of this study was to develop a competitive immunoenzymatic assay to measure total anti-HAV antibody levels using anti-HAV IgY as the capture and conjugated immunoglobulins. For this purpose, anti-HAV IgY was conjugated to horseradish peroxidase (HRP) and the optimal dilution of HRP-conjugated antibodies was evaluated to establish the competitive immuneenzymatic assay. The results obtained from our "in-house" assay were plotted on a receiver operator curve, which showed a sensitivity of 95% and a specificity of 98.8%, demonstrating that a competitive anti-HAV IgY immunoenzymatic assay developed "in house" could be used as an alternative to commercial assays that utilise IgG.

Declining prevalence of hepatitis A virus antibodies among children from low socioeconomic groups reinforces the need for the implementation of hepatitis A vaccination in Brazil

Age-related seroprevalence studies that have been conducted in Brazil have indicated a transition from a high to a medium endemicity of hepatitis A virus (HAV) infection in the population. However, most of these studies have focused on urban populations that experience lower incidence rates of HAV infection. In the current study, the prevalence of anti-HAV antibodies was investigated in children with a low socioeconomic status (SES) that live on the periphery of three capital cities in Brazil. A total of 1,162 dried blood spot samples were collected from individuals whose ages ranged from one-18 years and tested for anti-HAV antibodies. A large number of children under five years old (74.1-90%) were identified to be susceptible to HAV infection. The anti-HAV antibody prevalence reached ≥ 50% among those that were 10-14 years of age or older. The anti-HAV prevalence rates observed were characteristics of regions with intermediate level of hepatitis A endemicity. These data indicated that a large proportion of children with a low SES that live at the periphery of urban cities might be at risk of contracting an HAV infection. The hepatitis A vaccine that is currently offered in Brazil is only available for high-risk groups or at private clinics and is unaffordable for individuals with a lower SES. The results from this study suggest that the hepatitis A vaccine should be included in the Brazilian National Program for Immunisation.

Optimal time for repeating the IgM anti-hepatitis A virus antibody test in acute hepatitis A patients with a negative initial test / 대한간학회지

BACKGROUND/AIMS: The nonspecific clinical presentation of acute hepatitis A (AHA) mandates the detection of anti-hepatitis A virus IgM antibodies (IgM anti-HAV) in the serum for obtaining a definitive diagnosis. However, IgM anti-HAV might not be present during the early phase of the disease. The aim of this study was to determine the optimal time for repeating the IgM anti-HAV test (HAV test) in AHA patients with a negative initial test. METHODS: In total, 261 patients hospitalized with AHA were enrolled for this retrospective study. AHA was diagnosed when the test for IgM anti-HAV was positive and the serum alanine aminotransferase (ALT) level was > or =400 IU/L. Repeat HAV test was conducted after 1-2 weeks if the initial HAV test was negative but AHA was still clinically suspected. RESULTS: The results of the initial HAV test were negative in 28 (10.7%) patients. The intervals from symptom onset to the initial-HAV-test day and from the peak-ALT day to the initial-HAV-test day were significantly shorter in the negative-initial-HAV-test group, but on multivariate analysis only the latter was significantly associated with negative results for the initial HAV test (beta=-0.978; odds ratio [95% confidence interval]=0.376 [0.189-0.747]; P=0.005). The HAV test was positive in all patients when it was performed at least 2 days after the peak-ALT day. CONCLUSIONS: The results of HAV tests were significantly associated with the interval from the peak-ALT day to the HAV-test day. The optimal time for repeating the HAV test in clinically suspicious AHA patients with a negative initial HAV test appears to be at least 2 days after the peak-ALT day.

Clinical Factors Associated with Hepatitis A Virus Seropositivity in HIV-Infected Adults Living in a Country with an Epidemiologic Shift for Hepatitis A Virus Infection

The number of HIV-infected individuals susceptible to Hepatitis A virus (HAV) infection is increasing in Korea; however, it has proven difficult to devise a vaccination policy therefore because limited seroepidemiologic data exists for them. Accordingly, anti-HAV IgG was measured in 188 HIV-infected adults between July 2008 and July 2010. The nadir CD4+ T lymphocyte counts were not different between the HAV-positive and -negative groups (197 +/- 138 vs 202 +/- 129, P = 0.821). The only factor independently associated with seropositive status was age under 40 yr old (OR 0.017, P < 0.001). Our findings suggest that HAV vaccination in HIV-infected adults should be targeted at persons under the age of 40 yr.

Epidemiological and serological aspects of hepatitis A among children and teenagers in the city of Santos: a cross-sectional study / Aspectos epidemiológicos e sorológicos da hepatite A em crianças e adolescentes na cidade de Santos: estudo transversal

CONTEXT AND OBJECTIVE: Viral hepatitis A is still a concern at public health level in Brazil and around the world, due both to the number of affected subjects and the possibility of complications in the acute forms. The Brazilian Ministry of Health estimates that at least 70% of this country's population has already had contact with the hepatitis A virus (HAV). The aim here was to discover the prevalence of serological markers for the hepatitis A virus among children and teenagers at daycare facilities, kindergartens and elementary schools in the city of Santos. DESIGN AND SETTING: Cross-sectional study in kindergartens and elementary schools within the municipal education network in several regions of the city of Santos. METHOD: Students' family members were surveyed using a questionnaire and 4,680 finger-prick blood samples were taken and assayed by means of the ELISA technique. RESULTS: The general prevalence of anti-HAV IgG was 9.72% and, of these cases, 74.6% were reactive to anti-HAV IgM. There was higher prevalence of anti-HAV IgG among older children, females, children who played in streams, those whose homes were not connected to the sewage system, those whose parents had low education levels, those with low household income and those who did not live along the seashore. The prevalence of anti-HAV IgM peaked in the early years and subsequently fell, and it was lower on the hills and in the Northwestern Zone. CONCLUSION: The general prevalence of serological markers for hepatitis A was low in Santos.

CONTEXTO E OBJETIVO: A hepatite viral A continua sendo uma preocupação em nível de saúde pública no Brasil e no mundo, tanto pelo número de indivíduos atingidos, como pela possibilidade de complicação das formas agudas. O Ministério da Saúde estima que pelo menos 70% da população do Brasil já tiveram contato com o vírus da hepatite A. O objetivo foi conhecer a prevalência de marcadores sorológicos do vírus da hepatite A em crianças e adolescentes de creches e escolas de ensino infantil e fundamental na cidade de Santos. TIPO DE ESTUDO E LOCAL: Estudo transversal em pré-escolas e de ensino fundamental da rede municipal em diversas regiões da cidade de Santos. MÉTODO: Foi aplicado um questionário aos familiares dos estudantes e coletadas 4.680 amostras de sangue através de punção capilar para realização da sorologia pela técnica ELISA. RESULTADOS: A prevalência geral do anti-HVA IgG foi de 9,72% e, desses, 74,6% foram anti-HVA IgM reagentes. A prevalência de anti-HVA IgG foi maior entre as crianças mais velhas, meninas, aquelas que brincavam em córregos, sem rede de coleta de esgoto em sua moradia, de pais com baixa instrução, de baixa renda familiar e aquelas que não eram moradoras da orla. A prevalência de anti-HVA IgM teve pico nos primeiros anos e posterior queda e, no morro e Zona Noroeste, foi mais baixa. CONCLUSÃO: A prevalência geral dos marcadores sorológicos para hepatite A foi baixa em Santos.

Hepatite A: soroprevalência e fatores associados em escolares de São Luís (MA), Brasil / Hepatitis A: seroprevalence and associated factors among schoolchildren of São Luís (MA), Brazil

OBJETIVOS: Estimar a prevalência de anticorpos contra o vírus da hepatite A (antiVHA-IgG) em escolares de 7 a 14 anos de escolas públicas e privadas e identificar fatores demográficos, socioeconômicos e sanitários associados à prevalência de antiVHA-IgG. MÉTODOS: Estudo soroepidemiológico para detecção de antiVHA-IgG, de abril de 2002 a abril de 2004, em 462 escolares de São Luís, com idades compreendidas entre 7 e 14 anos, do ensino fundamental. Participaram 30 escolas aleatoriamente selecionadas, com probabilidade proporcional ao número de alunos matriculados, sendo 23 públicas e 7 privadas. Os dados foram obtidos por meio de questionário estruturado. Para se identificar variáveis independentemente associadas à prevalência do antiVHA-IgG, foi realizada análise de regressão de Poisson múltipla, sendo estimadas as RPs ajustadas e respectivos intervalos de confiança de 95 por cento. Somente permaneceram no modelo final aquelas variáveis associadas com a prevalência da hepatite A com p < 0,10. Foi adotado o nível de significância de 0,05 (α = 0,05). RESULTADOS: A prevalência de antiVHA-IgG foi de 64 por cento, sendo de 71,5 por cento nas escolas públicas e de 36,5 por cento nas privadas. Após análise multivariável, idade de 11 a 14 anos, mais de uma pessoa por dormitório e menos de dois banheiros por domicílio foi associada a maiores prevalências de antiVHA-IgG. Maior escolaridade dos pais esteve associada à menor prevalência de antiVHA-IgG. CONCLUSÕES: A hepatite A é endêmica nos escolares de São Luís, com taxa de prevalência semelhante àquela encontrada em outras regiões do país com condições socioeconômicas e sanitárias similares. Fatores historicamente associados à maior prevalência da hepatite A foram também identificados nesta população.

OBJECTIVES: To estimate the prevalence of antibodies to hepatitis A virus (antiVHA-IgG) in children aged 7-14 years from public and private schools, and to identify demographic, socioeconomic and sanitation factors associated with the prevalence of antiVHA-IgG. METHODS: Seroepidemiological study for the detection of IgG antiVHA. It was conducted from April 2002 to April 2004 with 462 elementary school students from São Luis, ranging from 7 to 14-years of age. Thirty schools randomly selected took part in the study, with a probability proportional to the number of students enrolled; 23 schools were public and 7 were private. Data was obtained through a structured questionnaire. In order to identify the variables independently associated with IgG antiVHA, the Poisson multiple regression analysis was performed, estimating the adjusted PRs and their 95 percent confidence intervals. The variables associated with the prevalence of hepatitis A with p < 0 were the only ones that remained in the final model. The level of significance of 0.05 (α = 0.05) was adopted. RESULTS: The prevalence of antiVHA-IgG was 64 percent, 71.5 percent in public and 36.5 percent in private schools. After multivariate analysis, age 11 to 14 years, more than one person per bedroom, and less than two bathrooms per household were associated with a higher prevalence of antiVHA-IgG. Higher parental education was associated with lower prevalence of antiVHA-IgG. CONCLUSIONS: Hepatitis A is endemic among schoolchildren in São Luís. The prevalence rate was similar to those found in other regions of the country with similar socio-economic and health conditions. Factors historically associated with a higher prevalence of hepatitis A were also identified in this population.

Soroprevalência de hepatite A em crianças e adolescentes / Seroprevalence of hepatitis A in children and adolescents

OBJETIVOS: Avaliar a soroprevalência de hepatite A (VHA) em crianças e adolescentes com idade entre 1 e 14 anos, e identificar fatores associados à infecção prévia. MÉTODO: Estudo epidemiológico transversal, realizado entre fevereiro e agosto de 2006, em Curitiba, Paraná, Brasil, e em sua região metropolitana. A análise laboratorial constituiu-se de pesquisa qualitativa de anticorpos totais para o VHA em amostra de sangue total. RESULTADOS: No estudo, 901 crianças e adolescentes foram incluídos. A distribuição por faixa etária foi: 237 (26,3 por cento) entre 1 e 4 anos; 313 (34,7 por cento) entre 5 e 9 anos; e 351 (39 por cento) entre 10 e 14 anos. A taxa de soroprevalência geral encontrada foi de 19,8 por cento, e por grupo etário foi de 3, 21,1 e 29,9 por cento (p < 0,01), respectivamente. Na análise multivariada, demonstrou-se que os fatores que, em conjunto, mantiveram associação positiva com as prevalências de anticorpos contra o VHA na população estudada foram: faixa etária de 5 a 9 e 10 a 14 anos, morar em casas com um ou mais habitantes por cômodo, frequentar refeitório comunitário e ter baixa renda per capita. CONCLUSÕES: Os resultados demonstraram uma baixa prevalência de anticorpos contra o VHA, o que justifica o uso de medidas profiláticas, que incluem a vacinação precoce.

OBJECTIVES: To determine the seroprevalence of hepatitis A (HAV) in children and adolescents aged 1 to 14 years, and to identify factors associated with a history of infection. METHOD: This was a cross-sectional epidemiological study, conducted form February to August 2006 in the city of Curitiba, Paraná, Brazil, and the surrounding municipalities (Greater Curitiba). Laboratory analysis comprised qualitative assay for total HAV antibodies in whole blood samples. RESULTS: A total of 901 children and adolescents were recruited for the study. Age distribution was as follows: 1 to 4 years, n = 237 (26.3 percent); 5 to 9 years, n = 313 (34.7 percent); and 10 to 14 years, n = 351 (39 percent). The global rate of seroprevalence was 19.8 percent, and seroprevalence rates by age group were 3 percent, 21.1 percent and 29.9 percent respectively (p < 0.01). Multivariate analysis demonstrated that the following factors, in combination, had a positive association with the prevalence rate of antibodies against HAV in the study population: age groups 5 to 9 and 10 to 14 years, living in a household with more than one inhabitant per room, shared eating area and low per capita income. CONCLUSIONS: The results show a low prevalence of antibodies against HAV, which justifies the use of prophylactic measures, including early vaccination.

Mudança na suscetibilidade à hepatite A em crianças e adolescentes na última década / Shifting susceptibility to hepatitis A among children and adolescents over the past decade

OBJETIVOS: Estimar a prevalência de anticorpos contra hepatite A (anti-VHA) em grupo de crianças e adolescentes de laboratório público e privado em Porto Alegre e comparar com estudo realizado na década anterior. MÉTODOS: Entre 2007 e 2008 foi realizado estudo transversal onde foram incluídas, consecutivamente, 465 amostras de soros de crianças e adolescentes entre 1 e 19 anos de idade para determinar a prevalência de anticorpos anti-VHA total. As amostras foram fornecidas por laboratório público (grupo 1), que atende somente Sistema Único de Saúde, e por laboratório privado (grupo 2), representando os estratos socioeconômicos mais baixo e mais alto, respectivamente. O teste foi realizado em único laboratório (eletroquimioluminescência, Roche Diagnostics). Resultados > 20 UI/L foram considerados positivos. RESULTADOS: A soroprevalência de anti-VHA no grupo 1 foi de 37,6 por cento e o percentual de positividade aumentou conforme a idade, variando de 19,4 por cento entre 1-4 anos a 54,1 por cento entre 15-19 anos. No grupo 2, a frequência de anti-VHA foi de 46,1 por cento e foi inversamente relacionada à idade, caindo de cerca de 50,0 por cento nas faixas etárias menores para 29,1 por cento aos 15-19 anos. Houve diminuição significativa na prevalência do anti-VHA nas crianças de 5-9 anos do grupo 1 (p = 0,03), quando comparadas com estudo realizado na década de 1990. CONCLUSÕES: Os resultados sugerem queda na endemicidade da hepatite A em Porto Alegre na última década e indicam maior suscetibilidade à doença em crianças e adolescentes, principalmente no estrato socioeconômico mais baixo.

OBJECTIVES: To estimate the prevalence of anti-hepatitis A virus (anti-HAV) antibodies in serum samples from children and adolescents obtained at two clinical pathology laboratories in the city of Porto Alegre, south of Brazil, and to compare findings to those of a study carried out in the 1990s. METHODS: In this cross-sectional study conducted between 2007 and 2008, 465 serum samples obtained from subjects aged 1-19 years were consecutively tested to determine the prevalence of total anti-HAV antibodies. Samples were provided by a public laboratory (group 1) that serves the Unified Health System exclusively, meant to represent the lowest socioeconomic strata, and by a private laboratory (group 2), meant to represent the higher socioeconomic classes. Tests were performed at a single laboratory using commercially available electrochemiluminescence kits. Antibody levels > 20 UI/L were considered positive. RESULTS: The seroprevalence of anti-HAV in Group 1 was 37.6 percent. The percentage of anti-HAV reactivity increased from 19.4 percent in the 1-to-4 group to 54.1 percent in the 15-to-19 group. In Group 2, overall anti-HAV positivity was 46.1 percent and was inversely correlated with age, declining from roughly 50 percent in the youngest groups to 29.1 percent in the 15-to-19 group. Comparison of sample findings to those reported in a 1990s study showed a significant reduction in anti-HAV prevalence among 5-to-9-year-olds in group 1 (p = 0.03). CONCLUSIONS: The results suggest that the endemicity of hepatitis A in Porto Alegre has been declining over the past decade, and that children and adolescents, particularly those in the lowest socioeconomic strata, are more susceptible to the disease.

Seroepidemiology of Hepatitis A in Korea: Changes over the Past 30 Years

This study aimed to assess the immune status of the Korean population against hepatitis A virus (HAV). Residual serum samples from 2008 to 2010 were collected from diagnostic laboratories and a total of 1,872 samples were analyzed. Anti-HAV seroprevalence was 57.3% in subjects aged 1-4 yr, 69.8% at 5-9 yr and decreased to 38.8% at 10-14 yr, 13.0% at 15-19 yr, and 11.7% at 20-29 yr. Seroprevalence increased with increasing age: 52.2% at 30-39 yr, 83.2% at 40-49 yr, 81.4% at 50-59 yr, 93.2% at 60-69 yr, and 95.1% at 70-79 yr. The most susceptible age group consisted of subjects aged 10-29 yr, especially those aged 20-29 yr. This pattern is markedly different from that in the past 3 decades, where the most susceptible group had consisted of children aged less than 10 yr and almost all subjects aged more than 20 yr had developed anti-HAV antibodies. Because of improvements in hygiene and introduction of hepatitis A vaccine, the age demographic of the susceptible population has shifted. These data are important for creating new prevention measures, including vaccination policies, to prevent and control outbreaks of hepatitis A in Korea.

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

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.

The Seroprevalence Rate, Vaccination Rate and Seroconversion Rate of Hepatitis A in Central Region of Korea / 대한소화기학회지

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.

Seroprevalence of IgG Anti-HAV in Hospital Employees below 40 Years Old / 대한소화기학회지

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.