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Hepatitis B has long been a serious public health problem in Greece. In recent years, a decline in hepatitis B infection is observed ascribable to many factors such as demographic and socioeconomic changes, medical precautions, use of disposable medical equipments, screening of blood donors and vaccination. We studied the prevalence of HBV infection in a sample of 1050 Greek male Navy recruits. 343 subjects (32.6%) had previously been vaccinated and were anti-HBs positive. We observed that during the last decade, the prevalence of immunes declined to 1.33% and the prevalence of any HBV marker declined to 2.28%. The HBsAg carrier rate declined from 3.9% in 1973 to 0.9% in 1986. Since then, it is stable at 0.95% because perinatal and vertical transmissions are still responsible for the majority of HBV chronic infections. Universal prenatal screening and infant immunization will contribute to a further decline of HBV infection.

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The objective of the study was to analyse the effect of knowledge of HIV serostatus on behaviours preventing the acquisition or transmission of HIV among European IDU, and to compare results with a previous similar study conducted 3 years before. Data were gathered in 1992-1993 during a retrospective multicentre cross-sectional study of IDU recruited in 11 European countries, in specialized centers and on the street. We compared, between groups with different HIV serological status (IDU who knew well before their HIV-positive serological status, IDU who knew their HIV-negative serostatus and IDU who did not know before their serological status), the respective proportions of IDU who reported that, during the six months prior to interview, (1) always used condoms, (2) never gave their used injecting equipment to other IDU, (3) always injected drugs safely. We only included IDU who had known their serological status for at least six months prior to interview. Results were compared to the similar survey conducted in 1990. From 2171 IDU recruited, data of 1334 IDU were included in the analysis. Compared with IDU who did not know their HIV serostatus, only IDU knowing their HIV-positive serostatus used condoms significantly more often (37% compared to 15%, rate ratio (RR): 2.4; 95% confidence interval (CI): 1.8-2.3) and never gave their used injecting equipment to other IDU (69% compared to 53%, RR: 1.3; 95% CI: 1.2-1.4). In comparison with the 1990 study, only condom use significantly improved and only for IDU who knew their HIV-negative serostatus (13% compared to 9%, RR: 1.6; 95% CI: 1.1-2.3). This study confirms among European IDU the relation between knowing own HIV serological status to preventive behaviours. However, there were only minor improvements between 1990 and 1992-1993, indicating that prevention of HIV transmission among IDU must be reinforced.

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Historically, Greece has had the highest burden of hepatitis B virus (HBV) infection in the European Union (EU). Heterosexual contact is the primary means of HBV transmission in Greece, accounting for approximately 30% of acute cases in adult males and 50% of acute cases in women of reproductive age [Kattamis C, Papevangelou G. Workshop Group: Greece. Vaccine 1995;13:S97-S98.]. In 1982, Greece implemented a hepatitis B prevention programme aimed at high-risk groups; unfortunately, this approach had little impact on disease incidence or prevalence. At the recommendation of the WHO and the World Health Assembly and after sustained lobbying by several scientific and medical associations in Greece, the Greek government decided to implement a national prevention programme for hepatitis B. The programme, in effect from early 1998, includes the screening of pregnant women, universal infant and adolescent immunization and immunization of high-risk groups.

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Hepatitis B (HB) vaccine has been included in the national immunization programmes of more than 90 countries world-wide. Its combination with DTP (diphtheria-tetanus-pertussis) and other childhood vaccines will lower administration costs, simplify vaccine administration and improve the logistics of vaccine delivery. It is believed that the combined vaccines will increase acceptance and vaccine coverage. The immunogenicity and reactogenicity of the various components should not differ when given separately or together. The combined vaccines DTP + HB, DT + HB, HA + HB, HB + Hib have already been developed and used in several countries and DTP + HB + IPV and DTP + HB + IPV + Hib combined vaccines are currently under development. Further studies are necessary to devise appropriate schedules adjusted to the epidemiological situations of each geographic region.

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Screening of pregnant women for hepatitis B surface antigen especially in countries with a high carrier rate as in Southern Europe is absolutely necessary for the control and elimination of the disease. In most Southern European countries screening of pregnant women is highly recommended. In Greece the carrier rate in pregnant women varies between 2.8 and 3.0%. However, only 63.1% of mothers at delivery had been screened before admission to the maternity hospital. To avoid legal problems arising from obligatory screening, educational campaigns, lectures, pamphlets and further measures to increase screening of pregnant women and administering hepatitis B immunoglobulin and vaccine should be taken.

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The recent development of safe and effective inactivated hepatitis A vaccines provides the opportunity to control hepatitis A. However, effective control will depend upon the duration of protection provided by the vaccine. Evaluation of persistence of antibodies over time is essential for the determination of vaccination schedules and strategies. For this purpose blood samples were obtained from 140 volunteers, 5 years after the administration of three 720 ELISA units (EU) doses of an inactivated hepatitis A vaccine according to a 0, 1 and 6 month schedule. All serum samples were tested for anti-hepatitis A virus (HAV) antibodies using a sensitive ELISA inhibition assay. All subjects, except one, had anti-HAV titres > or = 20 mIU ml-1. The geometric mean titre (GMT) was 1258 mIU ml-1. All individual titres were at least 10 times higher than the minimum protective level. According to the rate of antibody level decrease over time, the predicted duration of antibodies is estimated to be at least 20 years.

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A vaccine combining hepatitis B with diphtheria, tetanus and whole-cell Bordetella pertussis (DTPwHBV) would facilitate the attainment of universal vaccination of infants against hepatitis B. A candidate vaccine was administered to 42 infants beginning at 7-15 weeks of age. Antibodies were measured from pre- and postvaccination blood samples. After three doses, at least 94.9% of the infants were protected against hepatitis B, diphtheria and tetanus. Responses to B. pertussis were considered adequate. No serious adverse events were reported. These results indicate that this candidate vaccine is safe and immunogenic when administered to infants according to a three-dose schedule, with doses 2 months apart.

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Strategies for controlling the HIV epidemic include education and information campaigns for intravenous drug users (IDUs), as for all high-risk groups, and the provision of various public health measures and treatment. These can only be effective if the IDU is aware of them and has a favourable image of them. A study of 2330 IDUs in 12 European countries recorded awareness and opinions of various categories of measures and institutions. Of all measures, those mentioned most often related to availability of new injecting equipment; specifically unrestricted sales in pharmacies and needle exchanges, which were also thought to be more useful than anything else. Prompted awareness of rehabilitative institutions was well over 90% in most countries, but up to a quarter of IDUs did not trust them and up to one fifth did not think that they were useful. There appears to be a general need for more effective communication with IDUs to improve the image of the services available.

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The intrafamilial clustering of hepatitis A virus infections (HAV) in families with an index case of sporadic hepatitis A was studied. Four hundred and three family members (84.3%) of 113 children with acute hepatitis A admitted to the Paediatric Department of the West Attica Hospital were included in the study. Epidemiological data and serum samples were collected within 1 week after the patient's admittance to the hospital. Enzyme-immunoassays were used to detect recent or past HAV infections. The attack rate of HAV infections in susceptible family members was found to be similar in susceptible fathers (16.6%, 1/6), mothers (23.5%, 4/17) and siblings (18.1%, 37/204). The infected family members belonged to 22 families. The attack rate was found to be higher in families with a lower immunity level, while the social class was not found to play an important role. The administration of ISG prevented further spread of hepatitis A among those susceptible. Our data suggest that immunoglobulin for HAV prevention should be given not only to children but also to parents and other adult family members in areas with a low prevalence of anti-HAV among adults.

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OBJECTIVE: To study factors associated with HIV seropositivity among European injecting drug users (IDU). METHODS: Data on behavioural and other factors potentially associated with HIV status were collected retrospectively by personal interview with IDU (n = 2330) in a multicentre cross-sectional survey conducted in 12 European countries from 1989 to 1990. HIV status tested at the time of the survey was examined in relation to demographic data, history of imprisonment, travel to foreign countries, high-risk drug-using practices in the previous 6 months (re-using other IDU's injecting equipment without effective disinfection) and high-risk sexual behaviour in the last 6 months (multiple partners, unless none was IDU and condoms were always used). Analysis excluded IDU who claimed to be seropositive from previous testing. RESULTS: Imprisonment was significantly associated with current HIV status [odds ratio (OR), 1.70; 95% confidence interval (CI), 1.2-2.87]. High-risk drug-use practices were significantly associated with current HIV status in respondents not previously tested (OR, 2.86; 95% CI, 1.09-7.35) but not in respondents claiming to be seronegative. No significant association was found for high-risk sexual behaviour. CONCLUSIONS: Our experience supports the validity of retrospective investigation of behaviour in a population that is notoriously difficult to study. However, any interpretation of the apparently different associations of HIV status with high-risk sexual behaviour and high-risk drug-use practices must consider that factors tending to attenuate the correlations may operate differently in these two areas.

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The immunogenicities of hepatitis B virus vaccines containing S and pre-S2 regions were compared using two different schedules of immunization (A: 0-1-2-12 months and B: 0-1-6 months). Two hundred males and females aged 17-22 years were vaccinated with 20 micrograms per dose. The follow-up period was extended up to 13 months. One month after the booster dose anti-HBs were detected in 98.9% of those vaccinated with schedule A and 100% of those vaccinated with schedule B. Geometric mean titres (GMT) of anti-HBs were significantly higher with schedule A than schedule B, reaching GMT of 16269.7 mIU ml-1 and 4372.4 mIU ml-1, respectively, one month after the booster dose. Seroconversion rates for the anti-pre-S2 antibodies one month after the booster dose were 89.4% for schedule A and 76.6% for schedule B. GMT were 157.8 mIU ml-1 and 67.5 mIU ml-1, respectively. We conclude that both vaccines elicit high titres of anti-HBs and anti-pre-S2 antibodies. Immunity lasts longer in schedule A than in schedule B.

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OBJECTIVE: To study the effect of knowledge of HIV serostatus on behaviour for preventing the acquisition or transmission of HIV among European injecting drug users (IDU). METHODS: Data on behaviour and prior knowledge of HIV status were gathered during a multicentre cross-sectional survey of 200 European IDU recruited in 12 European countries in 1990. The respective proportions of IDU who (1) used condoms, (2) did not give their used injecting equipment to other IDU and (3) injected drugs safely (ether did not re-use other IDU's equipment or re-used it only after disinfection with bleach, alcohol or boiling water during the 6 months preceding interview were compared according to whether they knew their HIV serostatus for at least 6 months prior to interview. RESULTS: In comparison with IDU who had never been tested, IDU who knew that they were HIV-seropositive were more likely to always use condoms [rate ratio (RR) = 3.1; 95% confidence interval (CI), 2.3-4.2] and never gave their used equipment to other IDU (RR = 1.3; 95% CI, 1.2-1.5), but did not differ with regard to safe injecting practices (RR = 1.0; 95% CI, 0.9-1.1). Compared with IDU who had never been tested, IDU with a negative test tended to inject drugs safely more often (RR = 1.1; 95% CI, 1.02-1.2). There was no significant difference in condom use (RR = 0.7; 95% CI, 0.5-1.1). CONCLUSION: These results indicate that the knowledge of HIV serostatus may help to reduce HIV transmission from HIV-positive IDU to others through safer injecting and sexual behaviour. However, for HIV-negative IDU safer injecting behaviour appears to be better accepted than safer sexual behaviour.

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The frequencies of HLA antigens in 33 HIV seronegative and in 88 HIV seropositive haemophiliacs, who have been followed for at least 6 years since seroconversion or first HIV positive test, were evaluated in relation to disease susceptibility and disease progression. A high frequency of HLA-A2 and -DR2 antigens and a low frequency of HLA-A9 were found to characterize HIV seropositive patients (p < 0.05). Progressors to symptomatic CDC stage IV had a higher frequency of HLA-A9 (p < 0.01) and DR3. Rapid decline of CD4+ T cells in these patients was associated with HLA-A9, -DR1 and DR3. Our data suggest that HLA antigens may contribute to susceptibility to HIV infection and disease progression in Greek haemophiliacs.

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Improved standards of sanitation have contributed to a shift in the prevalence of hepatitis A in countries such as Greece. Children are now coming into first contact with the infection at an increasingly later age, leaving more adults susceptible to the disease. In military forces where close living conditions prevail, the likelihood of infection is even more pronounced. An inactivated hepatitis A vaccine has been developed and has been administered successfully to over 24,000 healthy children and adults. This vaccine would be of considerable benefit to military personnel worldwide. The reactogenicity and immunogenicity of a hepatitis A vaccine were evaluated in 200 female military recruits, aged from 17 to 23 years, vaccinated according to a primary vaccination schedule at 0 and 1 months with a booster dose at 6 months. Symptoms reported following vaccination were generally mild and transient. Soreness at the site of injection was the most frequent local symptom and malaise was the most common general symptom. Clinically significant increases in serum liver enzyme levels were not detected. All subjects had seroconverted after the primary vaccination course and maintained anti-HAV titres up to the time of the administration of the booster dose. The booster dose produced more than a tenfold increase in the geometric mean titre (GMT).

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In order to improve educational programmes directed at health care workers we investigated their knowledge, attitudes and practices in relation to HIV/AIDS. An anonymous self-administered questionnaires was distributed to 609 health care workers. Of these, 59.6% agreed to participate (42.4% of the medical doctors, 74.3% of the nurses and 79.6% of the laboratory technicians, health visitors and other health care workers). All studied groups believed that their knowledge of HIV modes of transmission (84.3%) was sufficient. In contrast, a relatively small percentage reported knowledge of the clinical spectrum of HIV infection (48.8%) and the diagnostic assays (57.6%). Nearly all the study participants believe (92.8%) that there is a risk of acquiring HIV infection during the hospitalization of HIV/AIDS patients. Obligatory screening of all patients was reported by nearly all participants (90.6%) as a chance to minimize their occupational risk. Although health care workers reported satisfactory knowledge of safety measures (87.0%), only 56.7% used gloves and 38.8% accept the hospitalization of HIV/AIDS patients. In spite of the educational programmes for AIDS in Greece, this study demonstrates that health professionals' knowledge and precautionary measures are not sufficient. As a result, a small percentage of them treat AIDS patients without discrimination. There is an urgent need to implement specific educational programmes for health professionals so that they will safely provide high quality care to people affected by HIV/AIDS.

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The risk of developing a chronic carriage state after acute hepatitis B infection in adults was evaluated. Two hundred and eighty-nine HBV-susceptible heterosexual partners of acute hepatitis B patients were used to investigate the effectiveness of post-exposure immunoprophylaxis; 75 of them received hepatitis B vaccine, 72 hepatitis B hyperimmune globulin (HBIG), 71 vaccine plus HBIG and 71 placebo. Participants were interviewed, clinically examined and serum specimens were taken at 1, 3, 6 and 9 months after their first intervention. Serum samples were tested for ALT and HBV markers (HBsAg, anti-HBc and anti-HBs) using radio immunoassays. Forty-six (15.9%) of the heterosexual partners examined were infected; the incidence of HBV infections was higher among placebo (18.3%, 13/71) and HBIG (18.1%, 13/72) recipients compared to vaccine (16.0%, 12/75) and HBIG plus vaccine (11.3%, 8/71) recipients, but the differences were not statistically significant. Infections were significantly more often subclinical after immunoprophylaxis (p = 0.03). HBsAg was detected in all eight clinical and in 13 of the 38 subclinical cases. In the remaining 25 subclinical cases HBV infections were diagnosed by the development of anti-HBc and anti-HBs during the follow-up period. Finally, all 46 cases studied cleared the HBsAg.

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Infection with hepatitis A virus (HAV) is still endemic in some Mediterranean areas. In most Northern Mediterranean countries, the incidence of acute icteric hepatitis in adults is increasing. This is due to the shifting of HAV infection to adulthood as a result of the decline of its overall prevalence due to improvements in socioeconomic, sanitary and hygienic conditions. The majority of adults remain susceptible and develop overt disease when infected, since the severity of disease is highly associated with age. Epidemics are now rare, but are more extensive when they do occur. They may sometimes be caused by accidental contamination of the water supply, but are usually due to contamination of food by diseased food-handlers or result from contaminated frozen foods. Outbreaks still may occur in day-care centres and in schools. Thus travelling to endemic areas is becoming the main source of HAV infection. Intrafamilial person-to-person spread also is an important source of infection. Transmission from children to parents and other adults may occur due to lack of immunity in the adult population. Selective immunization would further reduce the incidence of the disease. However, only inclusion of the vaccine in the routine programme of childhood immunization would guarantee the disappearance of hepatitis A.

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