Prévision de la séroprévalence de l'hépatite A dans la Wilaya de Setif en 2024 / Forecast of hepatitis a seroprevalence in the Wilaya of Setif in 2024

La séroprévalence des anticorps anti hépatite A (correspondant au taux d'immunisation) était de 100% à Sétif (Algérie), chez les personnes âgées entre 10 et 14 ans en 1986. Elle est passée à 70,4% en 2011. Partant de ce fait, les auteurs se proposent de prévoir cette séroprévalence, dans la même wilaya en 2024, à travers le modèle 'Logit binaire multiple', sur la base des données d'une enquête réalisée en 2011. La séroprévalence globale chez les sujets âgés entre 5 et 19 ans serait, selon les résultats de ce modèle, de 67% en 2024; les principaux facteurs associés à cette séroprévalence seraient l'âge, l'habitat, la taille des ménageset l'antécédent d'ictère. En conséquence, un programme de vaccination pourrait s'imposer comme une nouvelle stratégie de lutte contre la maladie dans la wilaya de Sétif.

The seroprevalence of anti-hepatitis A antibodies (corresponding to the immunization rate) was 100% in Sétif, in people aged between 10 and 14 years in 1986. It has declined to 70.4% in 2011. Starting from this fact, the authors propose to predict this seroprevalence, in the same wilaya (district) in 2024, through the 'multiple binary logit' model, based on data from a survey carried out in 2011. The overall seroprevalence in subjects aged between 5 and 19 years would be, according to the results of this model, 67% in 2024; the main factors associated with this seroprevalence would be age, habitat, household size and a history of jaundice. As a result, a vaccination program could establish itself as a new disease control strategy in Sétif.

Hepatitis A and E among immigrants and refugees in Central Brazil

ABSTRACT OBJECTIVE To estimate the prevalence of hepatitis A virus (HAV) and hepatitis E virus (HEV) among immigrants and refugees in Goiás, Central Brazil. METHODS Overall, 355 individuals were interviewed, and blood samples were tested for anti-HAV and anti-HEV IgG. Anti-HEV-positive samples were similarly tested for HEV RNA. RESULTS All participants were from Latin American countries, most of whom, young adult males. The overall anti-HAV IgG prevalence was 87.4% (95%CI: 83.5-90.4), of whom 94.9%, 75.6%, and 60% were from Haiti, Venezuela, and other Latin American countries, respectively (p < 0.001). Age above 19 years and more than 36 months residing in Brazil were associated with a higher prevalence of previous HAV and HEV infection, respectively. Of the children eligible for HAV vaccination according to the National Immunization Program, only eight (44%) had been vaccinated. The overall anti-HEV IgG prevalence was 6.5% (95%CI: 4.4-9.5). All anti-HEV IgG-positive individuals were Haitians, including a child born in Brazil. HEV RNA was detected in two of the anti-HEV IgG-positive samples. CONCLUSION The survey detected a high prevalence of anti-HAV and anti-HEV IgG among immigrants and refugees, and active HEV infection among some Haitian participants. Prevention measures are urgently required to interrupt enteric virus transmission in this emergent and vulnerable population.

Modeling the Long-term Antibody Response and Duration of Immune Protection Induced by an Inactivated, Preservative-free Hepatitis A Vaccine (Healive) in Children / 生物医学与环境科学（英文）

Objective@#Long-term seroprotection the hepatitis A vaccine is essential for the prevention of disease from the hepatitis A virus (HAV). Due to documented difficulties during decade-long follow-ups after receiving vaccines, statistical-modeling approaches have been applied to predict the duration of immune protection.@*Methods@#Based on five-year follow-up data from a randomized positive-controlled trial among Chinese children (1-8 years old) following a 0, 6 months vaccination schedule, a power-law model accounting for the kinetics of B-cell turnover, as well as a modified power-law model considering a memory-B-cell subpopulation, were fitted to predict the long-term immune responses induced by HAV vaccination (Healive or Havrix). Anti-HAV levels of each individual and seroconversion rates up to 30 years after vaccination were predicted.@*Results@#A total of 375 participants who completed the two-dose vaccination were included in the analysis. Both models predicted that, over a life-long period, participants vaccinated with Healive would have close but slightly higher antibody titers than those of participants vaccinated with Havrix. Additionally, consistent with previous studies, more than 90% of participants were predicted to maintain seroconversion for at least 30 years. Moreover, the modified power-law model predicted that the antibody titers would reach a plateau level after nearly 15 years post-vaccination.@*Conclusions@#Based on the results of our modeling, Healive may adequately induce long-term immune responses following a 0, 6 months vaccination schedule in children induction of memory B cells to provide stable and durable immune protection.

Perspectives on Acute Hepatitis A Control in Korea

Until 1995, the incidence of symptomatic acute hepatitis A was minimal and there were no cases of national outbreak in Korea. However, there was a nationwide outbreak of hepatitis A that peaked in 2009. In 2019, a total of 10,083 cases of acute hepatitis A were reported for seven months of the year according to the Korea Center for Disease Control and Prevention. This may be attributed to the proportion of susceptible subjects in the Korean population, as about 10 years have passed since herd immunity was induced by the epidemic occurring during the late 2000s. Recent studies have shown that the rate of seropositivity for anti-hepatitis A virus antibodies (anti-HAV) is the lowest in adults in their 20s and has not changed much over the past 10 years, and seropositivity of anti-HAV in adults in their 30s has continued to decline from 69.6% in 2005 to 32.4% in 2014. Most young adults who have not yet experienced hepatitis A and are not vaccinated are vulnerable to hepatitis A infection. This year's epidemic of hepatitis A is a predictable outcome for vulnerable populations. Therefore, effective acute hepatitis A control and prevention strategies are needed, particularly for those in their 20s and 30s.

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.

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.

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.

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)

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.

Seroprevalence of Anti-hepatitis B Virus, Anti-hepatitis A Virus, and Anti-varicella Zoster Virus Antibodies in Nursing Students from 2009 to 2013 / 병원감염관리

BACKGROUND: Nursing students may be exposed to patients with infectious diseases such as hepatitis B and hepatitis A through needle stick injuries or close contact during their clinical practice. This study surveyed the presence of antihepatitis B virus (anti-HBV), anti-hepatitis A virus (anti-HAV), and anti-varicella zoster virus antibodies in nursing students before the initiation of their clinical practice to help prevent subsequent infections. METHODS: From 2009 to 2013, the junior students of a nursing college in Jeollabuk-do were tested for antibodies against the hepatitis B, hepatitis A, and varicella zoster viruses before the initiation of their clinical practice. RESULTS: The students tested positive for anti-HBV (46.2-57.1%), anti-HAV (0-10.5%), and anti-varicella zoster antibodies (80.2-90.2%). No significant differences in the positivity rates were observed with respect to the year of their enrollment. CONCLUSION: This study was a survey of the seroprevalence of anti-HBV, anti-HAV, and anti-varicella zoster antibodies in nursing students before they started their clinical practice. The positivity rate of anti-HAV was lower than 10%. In order to prevent infection, it is necessary to test nursing students for the presence of antibodies against hepatitis B, hepatitis A, varicella, measles, mumps, and rubella, and check their vaccination history as recommended in the adult immunization schedule. Vaccination must be recommended for students who test negative for the respective antibodies.

Using immunoglobulin Y as an alternative antibody for the detection of hepatitis A virus in frozen liver sections

An increasing amount of research has been conducted on immunoglobulin Y (IgY) because the use of IgY offers several advantages with respect to diagnostic testing, including its easy accessibility, low cost and translatability to large-scale production, in addition to the fact that it can be ethically produced. In a previous work, immunoglobulin was produced and purified from egg yolks (IgY) reactive to hepatitis A virus (HAV) antigens. In the present work, this anti-HAV-specific IgY was used in an indirect immunofluorescence assay to detect viral antigens in liver biopsies that were obtained from experimentally infected cynomolgus monkeys. Fields that were positive for HAV antigen were detected in liver sections using confocal microscopy. In conclusion, egg yolks from immunised hens may be a reliable source for antibody production, which can be employed for immunological studies.

Prevalencia de anticuerpos totales contra el virus de la hepatitis A (VHA) en individuos adultos de la ciudad de Córdoba

Argentina es considerada un país de endemicidad intermedia para el virus de la hepatitis A (VHA). Debido a la introducción de la vacuna al calendario nacional (2005), es notable la reducción de notificaciones de casos clínicos por este virus. Sin embargo, en los últimos años el Ministerio de Salud de la Nación reportó un desplazamiento de la incidencia de casos, siendo los más afectados los adolescentes y adultos jóvenes. Como en Córdoba no existían datos actualizados de la prevalencia de anticuerpos en la población general adulta, el objetivo del trabajo fue proveer información actualizada sobre el estado inmunitario específico para VHA en individuos adultos de la ciudad de Córdoba después de cuatro años de la presentación oficial de la vacuna. Para ello, se realizó un estudio retrospectivo de seroprevalencia en muestras de sueros de 416 individuos adultos sanos residentes en Córdoba capital, sin antecedentes previos de vacunación y que fueron atendidos en centros de atención de salud durante septiembre de 2009 y septiembre 2010. Las muestras se clasificaron por grupos etarios y condiciones socio-económicas. La asociación de la prevalencia con la edad y la variable socioeconómica se determinó mediante modelos de regresión spline, en el marco de los modelos aditivos generalizados. La prevalencia global de anti-VHA fue del 73,5 %...

ABSTRACT: Hepatitis A virus (HAV) has shown intermediate endemicity in Argentina, but notification of clinical cases has decreased since the introduction of the vaccine in 2005. However, in recent years the Ministry of Health of Argentina reported a shift in the incidence of cases, being the most affected adolescents and young adults. In Cordoba, no data updated on the prevalence of antibodies in general adult population. So the objective was to provide information on HAV immune status of the adult population of Córdoba city after four years of the official introduction of the vaccine. The prevalence of anti-HAV was determined by EIA in 416 serum samples of people (without prior vaccination) from Córdoba city (sept2009–sept2010). Spline regression models were estimated under generalized additive models. In Córdoba, the global prevalence of anti-HAV was 73.5%...

Avaliação da utilização de ensaio imunocromatográfico para o diagnóstico e estudo de prevalência da hepatite A / Evaluation of an immunochromatographic assay for diagnosis and prevalence study of hepatitis A

O diagnóstico da infecção pelo vírus da hepatite A (HAV) através de testes de alta sensibilidade e especificidade pode levar um diagnóstico mais precoce e mais preciso,melhorando o prognóstico da doença. Deve também ser mencionado que um diagnóstico mais preciso pode tornar estudos epidemiológicos mais confiáveis e servir de base para a produção de programas de controle e erradicação mais efetivos. O objetivo deste estudo foi avaliar a utilização de um teste imunocromatográfico em surtos e estudos epidemiológicos de prevalência, triagem de candidatos para programas de vacinação e detecção de resposta imunológica pós-vacinação. Para este fim, 342 amostras provenientes de quatro grupos diferentes foram analisadas: (I) amostras de doadores de sangue (n= 96), (II) amostras de indivíduos vacinados contra a hepatite A (n= 46), amostras de surtos de hepatite A (III) (n=103) e (IV) amostras de casos esporádicos de hepatite A (n= 97). Estas amostras foram submetidas ao teste rápido SD BIOLINE HAV IgG/IgM e todos os resultados do teste rápido foram comparados com os resultados do ensaio imunoenzimático para HAV (EIA), que é o padrão ouro para detectar anticorpos contra o HAV...

The diagnosis of infection by the hepatitis A virus (HAV) through high sensitivity andspecificity tests can lead an earlier and more accurate diagnosis, improving the prognosis ofthe disease. It should also be mentioned that a more precise diagnosis can become morereliable epidemiological studies and as a basis for the production of more effective controland eradication programs. The aim of this study was to evaluate an immunochromatographictest in outbreaks and epidemiological studies of prevalence, screening candidates forvaccination and post-vaccination surveillance programs. For this purpose, 342 samples frompatients of four different groups were analyzed: (I) samples from blood donors (n=96), (II)samples from individuals vaccinated for hepatitis A (n=46), (III) samples from hepatitis Aoutbreaks (n=103) and (IV) samples from sporadic cases of hepatitis A (n=97). These sampleswere submitted to the rapid test SD BIOLINE HAV IgG/IgM and all results of the rapid testwere compared to the results of HAV enzyme immunoassay (EIA) that is the gold standard todetect antibodies against HAV. The results obtained for the group I showed that, 33.3%(32/96) were positive for anti-HAV IgG using the rapid test and 67.7% (65/96) were positivefor IgG anti-HAV by EIA. At group II, 71.7% (33/46) of the samples were positive for antiHAVIgG by EIA and none of them (0/33) was reactive by rapid test. Groups III and IV weretested for the presence of anti-HAV IgG and anti-HAV IgM antibodies...

Evaluation on the hepatitis A vaccine in preventing hepatitis A infection in Tianjin, from 2000 to 2011 / 中华流行病学杂志

<p><b>OBJECTIVE</b>Hepatitis A immunization strategies were carried out in 2001 in Tianjin. We wanted to evaluate the effectiveness of the strategies related to hepatitis A control programs and to provide the basis for further modification of the strategies.</p><p><b>METHODS</b>Descriptive epidemiology study was used to analyze the hepatitis A epidemic situation in 2000-2011 in Tianjin and to evaluate the disease reporting system. Hepatitis A vaccine coverage of target population and serum epidemiological study were carried out in 1999, 2005 and 2010 to check on the hepatitis A antibody levels so as to evaluate the immuno-barrier condition in the normal population. Cox-Stuart test was used to analyze the epidemic trend of hepatitis A and other intestinal infectious diseases in Tianjin.</p><p><b>RESULTS</b>The incidence rate of hepatitis A decreased from 2.89/100 000 in 2000 to 0.12/100 000 in 2011, and the percentage of hepatitis A in all types of viral hepatitis decreased from 8.02% in 2000 to 0.48% in 2011 in Tianjin. The positive rates of hepatitis A antibody also increased in the residents.</p><p><b>CONCLUSION</b>The hepatitis A vaccination program was successful in the programs on prevention and control of hepatitis A in Tianjin, China.</p>

Changes in the seroprevalence of IgG anti-hepatitis A virus between 2001 and 2013: experience at a single center in Korea

BACKGROUND/AIMS: The incidence of symptomatic hepatitis A reportedly increased among 20- to 40-year-old Korean during the late 2000s. Vaccination against hepatitis A was commenced in the late 1990s and was extended to children aged <10 years. In the present study we analyzed the changes in the seroprevalence of IgG anti-hepatitis A virus (HAV) over the past 13 years. METHODS: Overall, 4903 subjects who visited our hospital between January 2001 and December 2013 were studied. The seroprevalence of IgG anti-HAV was analyzed according to age and sex. In addition, the seroprevalence of IgG anti-HAV was compared among 12 age groups and among the following time periods: early 2000s (2001-2003), mid-to-late 2000s (2006-2008), and early 2010s (2011-2013). The chi-square test for trend was used for statistical analysis. RESULTS: The seroprevalence of IgG anti-HAV did not differ significantly between the sexes. Furthermore, compared to the seroprevalence of IgG anti-HAV in the early 2000s and mid-to-late 2000s, that in the early 2010s was markedly increased among individuals aged 1-14 years and decreased among those aged 25-44 years (P<0.01). We also found that the seroprevalence of IgG anti-HAV in individuals aged 25-44 years in the early 2010s was lower than that in the early 2000s and mid-to-late 2000s. CONCLUSIONS: The number of symptomatic HAV infection cases in Korea is decreasing, but the seroprevalence of IgG anti-HAV is low in the active population.

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.