Ibarra H

Immunogenicity and safety of a virosomal hepatitis A vaccine (Epaxal) in healthy toddlers and children in Chile.

In this open study, 20 toddlers and 80 schoolchildren received an intramuscular dose of Epaxal® and a booster dose 12 mo later to assess the efficacy and safety of this aluminium‐free, virosomal hepatitis A vaccine. Four weeks after primary vaccination, 94% of toddlers and 99% of schoolchildren had seroconverted, and all toddlers and 94% of schoolchildren remained seroprotected for 12 mo.

Placebo-controlled efficacy study of hepatitis A vaccine in Valdivia, Chile

A placebo-controlled, double-blind study on the efficacy of a hepatitis A vaccine (SmithKline Beecham Biologicals) was started in a region of Chile in September 1990, using hepatitis B vaccine as control. A total of 260 healthy children, 6-15 years of age, negative for antibody to hepatitis A virus (anti-HAV), antibody to HAV immunoglobulin M (IgM), hepatitis B surface antigen, and antibody to hepatitis B surface and core antigens by ELISA tests within 7 days before vaccination, were randomly assigned to two study groups: 128 children received the vaccine with a yellow label (group 1), and 132 children the vaccine with an orange label (group 2) at months 0, 1 and 6. Blood for serology and transaminase determination was drawn at months 1, 2, 6, 7 and 12. Both vaccines were tolerated equally well and no serious side effects were seen. In group 1 (presumed hepatitis A vaccine group), anti-HAV was detected (20% inhibition was used as the cut-off level) in 122 of 128 children (95.5%) tested at month 1, in 126 of 127 (99.2%) at month 2, in 126 of 127 (99.2%) at month 6 and in 126 of 126 (100%) at month 7. One anti-HAV seroconversion seen at month 1 was associated with presence of anti-HAV IgM and therefore probably represents HAV infection. Geometric mean anti-HAV concentration of the other children was 128, 342, 214 and 2301 mIU/ml at months 1, 2, 6 and 7, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis aguda por virus A, E y no A-E en adultos chilenos a fines de los años 90

BACKGROUND Sanitary and socioeconomic changes and the identification of new causative virus, have changed the epidemiology of hepatitis in Chile. AIM To study the natural history of acute hepatitis caused by virus A, E and non A-E in Chilean adults. PATIENTS AND METHODS A special study protocol was followed for patients with a clinical picture of acute hepatitis. Anti HAV IgM, anti HBc IgM, anti HEV IgG and IgM and Anti HCV antibodies were determined by ELISA. RESULTS Fifty nine patients (30 male), aged 15 to 58 years old were studied. Eighty nine percent had jaundice and 50 to 70% had malaise and abdominal pain. Virus A was positive in 80%, virus E in 7%. In 14% of patients, all viral markers were negative. The evolution was typical in 78%, biphasic in 14% and cholestatic in 5%. One patient had a prolonged and one a fulminant course. Mean ALT was 1148 U/l and mean total bilirubin was 5.5 mg/dl. Seventy three percent of cases occurred during early winter and spring and 27% during summer and early autumn. CONCLUSIONS The main etiology of acute viral hepatitis in Chile is virus A and most cases occur during the rainy season. Clinical features of hepatitis non A-E are similar to enteral transmission forms.

Seguimientos de anticuerpos contra hepatitis A y E en una cohorte de niños de bajo nivel socioeconómico

BACKGROUND The seroprevalence of antibodies against hepatitis A virus (HAV) is decreasing in many Latin American countries, along with improvements in sanitary standards. However, there is no information available about low socioeconomic status (LSE) populations. AIM To assess the evolution of hepatitis A and E virus antibodies in a cohort of LSE Chilean children. MATERIAL AND METHODS One hundred sixty eight children aged four years, 97 males, coming from public primary care clinics, were studied. Two blood samples were obtained with an interval of one year. Anti-HAV and anti-hepatitis E virus (HEV) antibodies, were detected by ELISA using Abbott kits. RESULTS Anti-HAV was positive in 19 children (11.3%). After one year of follow-up, only 10 children had sustained reactivity (52.6%). Fourteen children, initially negative, became positive during the follow up (9.4%). Antibody titers to HAV were significantly higher in samples that remained positive, compared with those that lost reactivity. Anti-HEV was found positive in two children (1.2%). One remained positive and the other became negative. CONCLUSIONS In this cohort of LSE Chilean children, the prevalence to antibodies against HAV and HEV is low. Follow-up detected loss of reactivity to HAV in nearly one half of the children, probably related to lower antibody levels.

Immunogenicity and tolerability of a paediatric presentation of a virosomal hepatitis A vaccine in Chilean children aged 1-16 years.

We assessed the immunogenicity of the paediatric dose of Epaxal(®) (0.25 mL) and the degrees of seroprotection achieved with the standard dose (0.5 mL) of Epaxal(®) or a dose of Havrix(®) Junior, in children in an open, randomised, controlled, multi-centre, parallel-group study conducted at 2 Chilean study centres. 360 healthy children and adolescents 12 months to <17 years of age not previously vaccinated against hepatitis A were enrolled. Subjects were randomised 2:2:1 to be vaccinated with either Epaxal(®) 0.25 mL [n=146], Epaxal(®) 0.5 mL [n=142] or Havrix(®) Junior [n=72] intramuscularly on Day 1 and after 6 months (26 weeks±14 days). Primary end point was the proportion of subjects seroprotected (anti-HAV antibody concentration ≥10 mIU/mL) in the ATP population at Month 1. All vaccines elicited high seroprotection rates at Month 1: 95.7% with Epaxal(®) 0.25 mL, 99.3% with Epaxal(®) 0.5 mL and 94.0% with Havrix(®) Junior. After the booster vaccination, all subjects demonstrated 100% seroprotection with all vaccines. Antibody concentrations were similarly high in all age groups. The paediatric presentation achieved antibody concentrations similar to those achieved with the 0.5 mL dose across the entire age range, and there were no differences across the range of body weights from 9.0 kg to 82.7 kg. All study vaccines were well tolerated and there were no AEs leading to discontinuation. Thus, the paediatric 0.25 mL dose of Epaxal(®) fulfilled the primary objective of showing non-inferiority to the adult 0.5 mL dose and to Havrix(®) Junior, in terms of seroprotection rates achieved. The results show the paediatric dose of Epaxal(®) to be an attractive option when conducting childhood-vaccination programmes.

Cambios en la epidemiología de las hepatitis virales en Chile y consideraciones en estrategias de prevención

The social and sanitary changes that Chile is experiencing willchange the epidemiologic profile of viral hepatitis. Virus A hepatitis will displace to older ages,and immunization plans with specific vaccines should be considered. The real prevalence ofhepatitis B may be higher, due to an underreporting of the disease. The education andvaccination of high risk groups should be reinforced. E virus hepatitis requires more research inrisk groups and in certain animal species consumed by humans. C virus hepatitis is the greatestchallenge as it causes chronic liver disease and is the main cause for liver transplantation (RevMed Chile 2007; 135: 229-39).(Key words: Hepatitis A, Hepatitis B; Hepatitis C; Hepatitis E; Viral hepatitis vaccines)

Presencia de anti-VHE en un estudio de cohorte de porcinos ¿reservorio animal de hepatitis E en Chile?

Swine hepatitis E virus (HEV) has a cross-reactionwith human anti-HEV antibodies. Therefore, pigs could be an animal reservoir, renderinghepatitis E as a zoonosis. The spread of this infection among infected pigs across countries wouldbe possible through trading. Previously, using an anti-human conjugate, we detected anti-HEVantobodies in adult pigs in Chile.BACKGROUND Swine hepatitis E virus (HEV) has a cross-reaction with human anti-HEV antibodies. Therefore, pigs could be an animal reservoir, rendering hepatitis E as a zoonosis. The spread of this infection among infected pigs across countries would be possible through trading. Previously, using an anti-human conjugate, we detected anti-HEV antobodies in adult pigs in Chile. AIM To detect anti-HEV (ELISA) in a cohort of swine at different ages. MATERIAL AND METHODS Two hundred pigs aged 42 to 360 days, divided in 20 groups of 10 animals were tested. Anti-HEV was detected by ELISA using anti-pig IgG horseradish peroxidase instead of anti-human conjugates. RESULTS Anti-HEV were detected in one animal aged 90 days, two animals aged 120 days, one animal aged 260 days and 2 animals aged 360 days, five pregnant sows and two old hogs. This represents a total of 14 animals or 7% of the sample. CONCLUSIONS There is a significant prevalence of anti-HEV in pigs from 90 days of birth, suggesting that these swine are a probable reservoir.

Estado actual de inmunidad para hepatitis por virus A en diversos grupos de adultos

Background: As sanitary and economic conditions improve, the prevalence of antibodies to hepatitis A is now significantly lower. Aim: To evaluate the prevalence of hepatitis A virus antibodies in healthy Chilean adults. Material and methods: Antibodies to hepatitis A virus were measured, using a commercial ELISA assay, in 215 voluntary blood donors (163 male, aged 19 to 30 years old) and 295 medical students and health personnel (156 male, aged 19 to 39 years old), residing in Valdivia, Chile. Results: Antibodies against hepatitis A virus were found in 68,2% of the total sample (351/510). Ninety percent of flood donors and 54% of health personnel and students were positive (p <0.01). Age specific prevalence in blood donors 19 to 22, 23 to 29 and 27 to 30 years old was 81,0%, 95,2% and 95,6% respectively. Among the same age groups in medical students, the prevalence was 47,9%, 53,2% and 61,9% respectively (p <0.01). Conclusions: This study indicates a reduction in the prevalence of hepatitis A virus antibodies among adults in Valdivia (Chile). Differences detected between individuals are probably related to different socioeconomic levels. Medical students have an increased risk for hepatitis A infections than the general population.

Virus de la hepatitis C en un grupo de pacientes hematológicos y oncohematológicos

Background: Little information is available in Chile about hepatitis C virus (HCV) in hematological and oncohematological patients. Aim: To evaluate the prevalence of hepatitis C virus markers in a group of hematological and oncohematological pediatric patients seen at Valdivia Regional Hospital. Patients and methods: Antibodies against virus C, determined by ELISA and viral RNA, determined using RT-polymerase chain reaction, were measured in 54 blood samples from children with hematological diseases (34 with Acute Lymphoblastic Leukaemia, 4 with Hodgkin Diseases, 4 with Haemolytic Anemia, 5 with Sarcomas, 2 with Non-Hodgkin Lymphoma, 2 with Thrombocytopenic Purpura, 1 with an Ependimoma, one with a Wilms Tumor and 1 with a Von Willebrand Disease). Results: All samples were negative for antibodies against hepatitis C virus. Viral RNA was found in four children, all with a diagnosis of acute lymphoblastic leukemia and who received chemotherapy and multiple transfusions. Conclusions: The prevalence of Viral RNA for hepatitis C virus in oncohematological patients in our study is high and associated with the use of chemotherapy and multiple transfusions (Rev Med Chile 2001; 129: 18-22)