Sera and questionnaires were evaluated retrospectively from 128 volunteer blood donors whose blood had been implicated in cases of clinically recognized posttransfusion hepatitis in recipients of one‐ or two‐unit blood transfusions between 1971 and 1977. Serologic markers of hepatitis B virus (HBV) infection were found in 23 per cent, compared to 9.7 per cent of 3,230 prospective blood donors. The prevalence of antibody to hepatitis A virus was similar among implicated donors (44%), prospective donors (58%), and among those implicated donors with (41%) and without (44%) HBV markers. Among implicated donors, none had a history at the time of donation of having had clinically recognizable hepatitis, 93 per cent had no history of prior blood transfusion, and 80 per cent had normal hepatic enzymes. Data from this study confirm that non‐A, non‐B hepatitis has been a common form of posttransfusion hepatitis in recent years, since 77 per cent of these implicated donors had no HBV serologic markers. In addition, these donors could not be distinguished by age, race, sex, history of clinical hepatitis or of prior blood transfusion, or in most cases by hepatic enzyme levels.
Six hundred and ninety‐three European Association for the Study of the Liver (EASL) members, belonging to one of the 15 European Union (EU) member‐states, were surveyed, through a standardized 45‐item questionnaire, on their medical practices regarding hepatitis C virus (HCV) infection. The response rate was 45%, roughly similar in all the countries concerned. Responders were classified into three groups according to their geographical origin: North, Centre and South. A consensus existed with regard to the necessity of HCV screening in well‐defined situations, such as history of blood transfusion, haemodialysis, haemophilia or intravenous drug addiction (90% of positive answers) while opinions substantially differed for vertical and nosocomial transmission of HCV. For the prevention of sexual and vertical transmission, opinions differed greatly: 22% were in favour of barrier methods for HCV‐positive subjects while 34% were against; 49% allowed breast‐feeding for babies born to HCV‐positive mothers while 14% were against. Conversely, there was relative homogeneity in the issue of domestic prevention (70% in favour of precautions). Algorithms for prescription of virological tests were inhomogeneous (recombinant immunoblot assay was used by 60%; polymerase chain reaction was requested by 77% when alanine aminotransferase (ALT) was elevated vs 89% when normal); medical evaluation varied according to ALT values: liver biopsy and liver ultrasonography were carried out in 90 and 91% vs 40 and 70% for increased and normal ALT, respectively. Thirty per cent of respondents advised patients to stop alcohol consumption and 60% advised moderation. Two‐thirds of the responders did not take into account histological severity and virological parameters before initiating antiviral therapy. Eighty per cent of the participants claimed that they administered interferon (IFN) for 12 months. For most of the items studied, there was a large variation, not only between the three groups, but also within each group. Ninety‐two per cent of the responders claimed that they were well trained on HCV but they were rather critical of the quality of the information diffused (satisfaction rate: 45%). Altogether, our survey demonstrates that preventive and medical practices towards HCV are not homogeneous throughout the EU; this suggests the need for a European consensus conference in this regard.
An epidemiological study and the simultaneous evaluation of anti-HAV antibody using radio immunoassay (RIA) and immunoadherence hemagglutination assay (IAHA) was performed during three hepatitis A epidemics in the Tours area (France). Fifty-seven sera from 35 subjects with viral hepatitis type A and 16 sera from nine children who did not develop any clinical signs of hepatitis were studied. The more explosive epidemic occurred in an institution for mentally retarded children (attack rate 68%). The two major outbreaks observed were due to the introduction of the institutions of individuals infected with hepatitis A virus. Two out of three of the index cases had a seafood dinner three to four weeks before onset of jaundice. Sera taken one week after jaundice were always found to be anti-HAV positive by both RIA and IAHA, and sera taken more than three days before the appearance of jaundice were negative by both methods. Sera taken at the peak of the transaminase elevation were anti-HAV positive by RIA but only one out of two were positive by IAHA. The anti-HAV titre by RIA increased from the time of the appearance of jaundice and the highest titres, over 1/20000 were seen only after several months. Observations of subjects in close contact with patients who seroconverted without any manifestation of hepatitis, confirmed the existence of clinically mute infections.
As part of the evaluation of a new combined Diphtheria-Tetanus-Pertussis-Poliomyelitis (DTP-Polio) inactivated vaccine, the pertussis agglutinin response was studied in 62 infants, two to three months old. Each dose of vaccine combined these antigens in a 0.5 ml volume, and contained at least four International Protective Units of pertussis antigen adsorbed on aluminium hydroxide. Infants were vaccinated with three doses of DTP-Polio vaccine at two month intervals. Pertussis agglutinin determinations showed a satisfactory response after two DTP-Polio vaccine doses. Although higher agglutinin titres were apparent after three doses than after two, no significant difference was observed in the seroconversion rate after two or three doses (88.8% and 96.3% respectively). The DTP-Polio vaccine would thus seem suitable for use in a two-dose primary immunization schedule against pertussis.
The safety and immunogenicity of vaccines are demonstrated before they are made available to doctors and the public. However, the protective activity against the disease for which a vaccine was designed can only be accurately measured in field trials. This involves its large-scale use in the target population. Epidemiology is the best approach to assess the results. This approach is based on the comparison of the incidence of the disease among vaccinated and non-vaccinated individuals. Three techniques can be used to estimate vaccine efficacy in a population: screening methods; cohort studies; and case control studies. These methods are most often used during epidemics, and this article discusses their application in this context. The validity of these methods depends on three criteria: that the administration of the vaccine to individuals in the population is random; that contacts between individuals in the population is random, and that vaccinated and non-vaccinated individuals have the same probability of encountering the infectious agent; that the population has equal susceptibility to the infection (other than the effect of the vaccine). If these conditions are not respected, the results of the analyses can be biased. The method involving calculation of the secondary attack rate in the families of index cases is the method where these conditions are most likely to be fulfilled.
Durante alguns anos, a Franca foi confrontada com uma disseminacao rapida da resistencia aos antibioticos em hospitais e na clinica geral, apesar das varias recomendacoes emitidas para resolver este problema. Em 1999, o Institut de Veille Sanitaire (Instituto de Saude Publica) efectuou uma experiencia colectiva seguida por uma consulta nacional que reuniu todos os profissionais de saude envolvidos na resistencia aos antibioticos. Esta consulta foi concluida com a elaboracao de propostas na perspectiva de um plano nacional de accoes para controlar a resistencia aos antibioticos, apresentadas ao Ministerio da Saude frances.
