Use of filter paper disks for hepatitis A surveillance.

BACKGROUND: Venous blood collection is a cumbersome and uncomfortable procedure during hepatitis A surveillance. Collection of capillary blood by finger prick is an alternative method. AIM: To evaluate the reactivity of capillary blood/anti-hepatitis A virus (HAV) IgG stored on filter paper disks for detection of anti-HAV antibody. METHODS: Venous blood specimens were collected from healthy individuals. Simultaneous capillary blood specimens obtained by finger prick were stored on filter paper disks. A reference standard of anti-HAV IgG in known concentrations was spotted on filter paper disks. The reactivities of anti-HAV IgG and capillary blood specimens eluted from filter paper disks were tested by blocking ELISA for detection of anti-HAV antibody. The results were evaluated by comparing optical density (OD) and neutralization values with those obtained for WHO anti-HAV IgG stored in liquid phase and homologous venous blood specimens, respectively. RESULTS: Among both venous and capillary-blood specimens stored for 10 days, percent neutralization shown by the same 46 specimens was > 50 and that of the same 3 specimens was < 50, indicating anti-HAV positivity and negativity, respectively. There was significant correlation between the OD values displayed by anti-HAV IgG from liquid phase and that eluted from filter paper disk (p < 0.01). Sixteen serum specimens stored for a period of 2 months showed results similar to those of the corresponding filter paper disk elutes. CONCLUSION: Use of filter paper disks could be a suitable choice for pre- and post-immunization collection of blood specimens during hepatitis A surveillance.

Prevalence of enterically transmitted hepatitis viruses in patients attending a tertiary--care hospital in south India.

The prevalance of enterically transmitted hepatitis viruses, namely, hepatitis A virus (HAV) and hepatitis E virus (HEV) were studied in 404 patients with acute hepatitis attending a tertiary-care hospital in south India. Presence of current HAV/HEV infection was ascertained by the demonstration of IgM antibodies. In 381 patients tested for both agents, HAV IgM was present in 51(13.3%) and HEV IgM present in 66(17.3%). There was dual infection in 3 males (0.8%). HEV infection was seen mostly in older children and adults with only 5.5% occurring in children < 12 years of age. HAV infection was commonly seen to occur in < 12 years of age group (52.7%). One hundred and twenty-six patients were from the Vellore region, among whom HAV and/or HEV aetiology was observed in 28.5%. In this region there did not appear to be any correlation between occurrence of acute hepatitis due to these viruses and rainfall or environmental temperature. Acute hepatitis due to enteric hepatitis viruses was seen throughout the year.

Immunogenicity and safety of an inactivated hepatitis A vaccine in Taiwanese adults and children.

The safety and immunogenicity of an inactivated hepatitis A vaccine (AVAXIM, 160 antigen units) was evaluated in 190 subjects: 50 children aged from 2 to 5 years, 70 children aged from 6 to 17 years and 70 adults aged from 18 to 30 years in a monocentric, open, non-controlled, phase III trial conducted in Taipei, Taiwan from December 1996 to October 1997. The vaccine was administered intramuscularly, with a two-dose schedule 6 months apart. Clinical adverse events were monitored during the seven days following each injection. Hepatitis A virus (HAV) antibody titers were measured by modified radioimmunoassay on the day of inclusion and four weeks after both the first dose and booster injection. Among the 190 subjects who received the first dose, 174 (91.6%) were initially HAV seronegative and 16 (8.4%) were HAV seropositive at inclusion. One hundred and seventy-four subjects (91.6%) received the booster dose and completed the study. One month after the first dose, all the subjects, whatever the age, presented HAV antibody titers over 20 mIU/ml. In children (2 to 17 years), the GMT was 136 mIU/ml at week 4 and 7,906 mIU/ml four weeks after the booster dose. In adults (> or = 18 years), GMT values were 93 mIU/ml at week 4 and 3,655 mIU/ml four weeks after the booster. These results show a strong anamnestic response to the second dose of vaccine and are compatible with long-term antibody persistence in each age group. The vaccine was safe and well tolerated. No vaccine-related serious adverse event occurred. No immediate reaction occurred. The majority of the reactions were reported by adults after the primary injection. Local reactions (pain and redness) were reported by 9.0% and 4.0% of the subjects after the primary and the booster doses, respectively. Systemic reactions (mainly myalgia/arthralgia or asthenia) affected less than 10% of the subjects after the first dose and less than 3% after the booster. Results from this study in a Taiwanese population are consistent with those obtained with the same vaccine in previous European studies in children and adults, and suggest that AVAXIM (160 AU) is suitable for use in all subjects aged over 2 years.

Seroprevalence of hepatitis A virus and varicella zoster antibodies in a Javanese community (Yogyakarta, Indonesia).

Hepatitis A virus (HAV) cause an acute inflammation of the liver. Varicella-zoster virus (VZV) cause chickenpox (varicella) and herpes zoster. Effective vaccines against hepatitis A and varicella are available for children, adolescents and adults. In order to implement an appropriate vaccination policy, a baseline to assess the potential benefits and sections of the population who would benefit most are required. We investigated seroprevalence of hepatitis A virus and varicella zoster antibodies in a Javanese community. A total of 1,103 subjects were studied. The 600 subjects aged 4 to 9 years were sampled between 23 October and 2 November, 1995. The other subjects were sampled between 12 October and 1 November, 1996. The overall prevalence of anti-HAV in cohort was 28.7%. Anti-HAV seroprevalence rates were below 30% until the age of 15 and below 40% until the age of 25. The anti-varicella seroprevalence showed only in two thirds of seropositive population at the age of 15. The results of the study have implications for vaccination strategies for both hepatitis A and varicella zoster.

Current seroprevalence of hepatitis A virus infection among kindergarten children and teachers in Taiwan.

Taiwan was a hyperendemic area for hepatitis A virus (HAV) infection before the late 1980s. The seroprevalence of HAV infection was higher than 90% with most HAV infection occurring during childhood. This study was to estimate the seroprevalence of HAV infection among preschool children in central Taiwan. A community-based survey was carried out in 54 kindergartens in 10 urban areas, 10 rural areas and 2 aboriginal areas randomly selected through stratified sampling. Serum samples of 2,549 healthy preschool children and 104 teachers in study kindergartens were screened for the HAV antibodies (anti-HAV) by means of a commercially available microparticle enzyme immunoassay (AxSYM HAVAB). Among aboriginal kindergarten children, more than 96% of them were anti-HAV seropositive due to a mass HAV vaccination program. In urban and rural areas, kindergarten children had a very low prevalence of anti-HAV (0.4%) in contrast to a high seroprevalence in their teachers (78%). There was no gender difference in seroprevalence of anti-HAV, while the anti-HAV seroprevalence was significantly higher in urban areas than in rural areas. Crowdedness of living in urban areas might facilitate the person-to-person transmission of infectious agents.

Comparison of the reactogenicity and immunogenicity of two different dose levels of hepatitis A vaccine in healthy children and adolescents.

An open study was performed to compare the reactogenicity and immunogenicity of an inactivated hepatitis A vaccine administered in two different doses and schedules to 460 healthy volunteers aged 3-18 years. Participants were randomized to two groups to receive either two doses of 720 ELISA Units (EL.U) inactivated hepatitis A per 0.5 ml dose according to a 0, 6-month schedule, or three doses of 360 EL.U according to a 0, 1, 6-month schedule. Transient local injection soreness was the most commonly reported symptom in almost half of both groups with no serious adverse events. One month after the primary course (one dose of 720 EL.U and two doses of 360 EL.U), 99% of 720 EL.U vaccinees had seroconverted, compared with 100% seroconversion in the 360 EL.U group. All vaccinees were seropositive after the booster dose of both vaccines with geometric mean anti-HAV titers of 2,359 and 2,967 mIU/ml in the 720 EL.U and 360 EL.U groups, respectively. The vaccine containing 720 EL.U of antigen per dose offers the advantage of convenience and acceptance of immunization afforded by a two-dose course of vaccination accompanied by a comparable antibody response with that achieved after three doses of vaccine containing 360 EL.U of antigen per dose.

Anticuerpos séricos contra el virus hepatitis A en sujetos de nivel socioeconómico medio y bajo en comunas urbanas de Santiago / Serum antibodies against hepatitis A virus among subjects of medium and low socioeconomic levels in urban Santiago

Background: The epidemiology of hepatitis A virus (HAV) infection is closely associated to the level of hygiene and sanitation of the population. Newly industrialising areas experience a transition from high to intermediate endemicity, which is characterized by a shift in the exposure age to HAV, from early childhood to school ages or adolescence. Aim: To measure the prevalence of HAV antibodies in subjects living in urban Santiago. Subjects and methods: A HAV antibody survey in five medium and low socioeconomic level urban districts of northern Santiago, was conducted in 1996. Healthy subjects aged 1 to 39 years old were recruited from randomly selected households. Results: Five hundred three subjects were studied. Anti HAV antibodies were found in 13.2, 29.5, 59.6, 78.1, 95.6 and 98.2 percent of individuals aged 1 to 4, 5 to 9, 10 to 14, 15 to 19, 20 to 29 and 30 to 39 years old, respectively. Conclusions: The profile of positive antibodies is compatible with an intermediate pattern of transmission of HAV. The current data supports the idea that infection is shifting towards older ages. A progressive increase in the number of susceptible school age children and teenagers is propitious for the occurrence of common source hepatitis A outbreaks

Vacunas anti hepatitis A: estado del arte / Hepatitis A vaccines: state of the art

La hepatitis A es una antigua enfermedad infecciosa importante a nivel mundial. Se trasmite vía fecal-oral por lo que su incidencia está relacionada con los niveles higiénicos y de saneamiento en cada comunidad. Esta revisión contempla la historia del desarrollo de las vacunas inactivas y de las atenuadas. En una perspectiva futura se muestra el desarrollo de vacunas inactivas en liposomas y combinaciones de vacunas. Se analizan la inmunogenicidad, protección a largo plazo y eficacia de las vacunas inactivas autorizadas por el FDA de EE.UU- HAVRIX© y VAQTA©, haciendo hincapié en el mecanismo mediante el cual las vacunas inactivas son capaces de interrumpir la transmisión del virus, responsables de la salud del niño y conocedores del medio ambiente en que éste se desarrolla, decidirán en conjunto la indicación individual de la vacuna. En términos de salud pública, las estrategias de vacunación dependerán de las realidades epidemiológicas de cada país y comunidad, teniendo presente que existen lugares en el mundo con alta, intermedia y baja endemia. En Chile replantearse las medidas de control de la hepatitis A. El análisis de las tendencias de morbilidad, comprueba que prácticamente no ha habido impacto favorable de las medidas de higiene y saneamiento ambiental. Por otro lado, los estudios de seroprevalencia muestran una tendencia en el desplazamiento de los susceptibles a edades mayores en quienes la hepatitis A implica mayor gravedad

Prevalencia de anticuerpos anti-hepatitis A en escolares en la década actual / Prevalence of antibodies against hepatitis A virus in chilean school age children

Background: As sanitary conditions of a population improve, hepatitis A virus infection occurs at higher ages,thus decreasing the prevalence of antibodies against the virus. In the eighties, the prevalence of antibodies among children was 97 percent and depended on the socioeconomic level. Aim: To assess the prevalence of antibodies against hepatitis A virus in school age children living in Valdivia. Subjects and methods: Two thousand three hundred thirty three school age children were studied. Total antibodies against hepatitis A virus were detected using an ELISA kit from Abbott. Children were stratified in age groups and school were classified as private, subsidized, municipal or foster homes. Results: Antibodies were positive in 65 percent of children (59 percent in children aged 6 to 8 years old, 66 percent in children aged 9 to 11 years and 69 percent in children aged 12 to 15 years. In private schools, the prevalence was 26 percent, in subsidized schools the figure was 54 percent, in municipal schools 73 percent and in foster homes 91 percent. Conclusions: The general prevalence of antibodies against hepatitis A virus is higher in low socioeconomic level children. There is a global decrease in the prevalence of these antibodies in the last years

Subacute hepatic failure in hepatitis A.

Hepatitis A is usually thought to be innocuous. We report a woman who developed subacute hepatic failure due to hepatitis A and died of the disease.

Prevalencia de anticuerpos contra el virus de la hepatitis A (VHA) en una poblacion de niños mexicanos / Prevalence of hepatitis A virus antibodies in Mexican children

Se analizaron los datos con relación a la prevalencia de anticuerpos IgG e IgM contra el virus de la hepatitis A (VHA), mediante la técnica de ELISA en 450 ninos sin antecedentes de hepatitis, con edades comprendidas entre los 3 meses y 17 años de edad, que acudieron a consulta al Instituto Nacional de Pediatría de la ciudad de México en el período comprendido de septiembre de 1992 a junio de 1993. La prevalencia de anticuerpos IgG en la población estudiada, fue del 83.6 por ciento. De los niños menores de un año el 50 por ciento mostraron anticuerpo, el 80 por ciento a los 3 años 80 por ciento, y el 96 por ciento a los 10 años de edad. Sólo 9 niños de los 450 tuvieron además anticuerpos IgM contra el virus de la hepatitis A. Se concluye que la prevalencia de HVA en la población que estudiamos es semejante a lo referido hace 13 años en México.

Soroepidemiologia da hepatite A em dois grupos populacionais economicamente distintos de Porto Alegre / Serum epidemiology of hepatitis A in two economically distinct population groups of Porto Alegre

Para avaliar a prevalência da hepatite viral aguda A (HAV),assim como sua relaçao com nível socioeconômico, idade, sexo, cor, história clínica prévia e aplicabilidade da vacina anti-HAV. foram estudados 387 crianças e adolescentes de Porto Alegre. Cento e noventa e nove pacientes de baixo nível socioeconômico eram provenientes do ambulatório da Santa Casa de Misericórdia de Porto Alegre e 188 de alto nível socioeconômico, do Laboratório Weinmann, um laboratório particular. Dos 199 pacientes da Santa Casa, 101 (51 por cento) apresentaram exames positivos para o anticorpo anti-HAV total; a prevalência encontrada foi aumentando de acordo com a faixa etária: de 20 por cento aos quatro anos a 71 por cento aos 19 anos de idade. No Laboratório Weinmann, 20 pacientes apresentaram anticorpo anti-HAV total positivo, o que corresponde a 11 por cento da populaçao total. Nesse grupo, a prevalência também aumentou de 3 por cento aos quatro anos para 17 por cento aos 19 anos. Nao houve diferença significativa entre os sexos nos dois grupos estudados. Quanto à cor no grupo da Santa Casa, os pacientes negros apresentaram maior positividade para o anticorpo anti-HAV, que foi atribuída a possível nível socioeconômico ainda mais baixo. Apenas um de cada dez pacientes anti-HAV positivo tinha história de hepatite no passado. Com base nesse estudo, sugere-se que uma vacina contra HAV de baixo custo, eficaz e de resultados duradouros deveria ser introduzida no esquema habitual de vacinaçao das crianças.

Age-specific prevalence of hepatitis A antibody in Thai children.

Age-specific prevalence of anti-HAV was determined for 3 groups of children whose mean ages were 12.6, 20.7 and 52.5 months. There were 41, 43 and 99 children in the respective age groups. All children were healthy, from middle to low socioeconomic families in Bangkok and vicinity. None of the children in the two younger age groups had anti-HAV antibody while 2 of 99 children in the oldest age group did. One of them resided in central Bangkok (Amphoe Dusit) and the other in Nonthaburi Province. The overall prevalence of anti-HAV in children under 5 years old was 1.1%. This demonstrates that hepatitis A transmission rates in Bangkok are very low when compared to ten years ago when prevalence rates were as high as 50-65%. From this study hepatitis A vaccine is recommended for 4-5 years old children in Bangkok. We need more epidemiologic data concerning hepatitis A transmission in Thailand before we can consider hepatitis A immunization for the whole country.

Outbreak of hepatitis A in a college traced to contaminated water reservoir in cafeteria.

A sharp but short outbreak of hepatitis A occurred in a college during September and October 1992. The epidemic pattern suggested a common source. The attack rate of clinically recognizable hepatitis A was 8% all cases were HAV IgM positive. Among 31 students with minor symptoms but without jaundice 8 (26%) were also HAV IgM positive, as were 8 (10%) of 77 totally asymptomatic students tested. A case control study of eating and drinking habits of the students showed no other significant differences other than that 45 of 56 cases and 18 of 34 controls interviewed had filled their water glasses by dipping them in a overflow water reservoir. This gives an odds ratio of 3.8. The reservoir was heavily contaminated with coliform bacteria and the residual chlorine was at lower than standard concentration, whereas other water resources were clean. It is suggested that the reservoir had been contaminated with hepatitis A virus by somebody with fecally contaminated hands a couple of weeks prior to the beginning of the outbreak.

Intragastric infection induced in marmosets (Callithrix jacchus) by a Brazilian hepatitis A virus (HAF-203)

Several specied of non-human primates have been used in studies on experimental infection with hepatitis A virus (HAV). Attempts to infect a South-American marmoset (Callithrix jacchus) with a Brazilian HAV isolate (HAF-203) are described here. Four seronegative animals were inoculated intragastrically and one was sacrificed on day 11,20,47 and 62 after infection. One uninfected animal was included as control. Liver, small intestine, lymph node, spleen and kidney samples were collected for histological diagnosis and immunocytochemistry studies. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) serum enzymes and anti-HAV antibodies were monitored by a colorimetric procedure (Abbott) and an enzyme immunoassay (ELISA), respectively. Feces were collected daily for HAV antigen (HAVAg) detection by ELISA. Increased levels of HAVAg were detected in hepatocytes 11 days after infection, with a gradual decrease during the course of infection. Shedding of HAVAg in feces was observed from the late incubation to the early acute phase (20th day to 47th day after infection). The end of the incubation period was indicated by the initial increases in serum ALT and AST. Severe hepatic lesions such as piecemeal necrosis and bridging necrosis were detected during the acute phase, coinciding with the maximum transaminase levels and the appearance of anti-HAV antibodies. On the 62nd day (convalescent phase), the hepatic tissue showed evidence of regeneration and the transaminase values had returned to baselines. The serological, biochemical, antigenic and histological evidence of hepatitis A was similar to that observed in several primate models inoculated with other HAV isolates. The data suggest that C. jacchus can be a valuable model for the study of hepatitis A and for the evaluation of HAV vaccines

Hepatitis A, B and C seroprevalence in Pakistan.

A cross sectional study was conducted to determine the seroprevalence of Hepatitis A, B, and C virus in healthy Pakistani children. HAV IgG antibody was assayed in 258 subjects and it was found that 94% children by 5 years of age had HAV IgG-antibody. The overall seroprevalence of HAV IgG antibody was 55.8% and IgM 5.3%. HBVsAb levels assayed in 236 healthy children showed a seroprevalence of 2.97%. Similarly, HCV antibody seroprevalence was found to be a low 0.44% in healthy children. HAV is a major cause of Hepatitis, as compared to HBV and HCV which are of low endemicity.