Immunogenicity of low doses of recombinant hepatitis B vaccine in young males.

A trial of low doses (1.25 and 0.625 micrograms) of recombinant hepatitis B vaccine in 110 males aged 17-19 years is reported. Follow-up was extended to one year and further data are reported for participants from earlier trials of 10, 5 and 2.5 microgram doses for comparison. Seroconversion rates after the booster dose were 94% at 1.25 micrograms and 89% at 0.625 micrograms, compared to 100% at higher doses. Geometric mean titres (GMT) of antibody to hepatitis B surface antigen (anti-HBs) were significantly lower with the 0.625 microgram dose than with 1.25 micrograms at all times, reaching a GMT of 42.6 IU l-1 and 152.9 l-1, respectively, after the booster dose. GMT values at 12 months were 513.9, 510.0, 320.7, 46.5 and 13.3 IU l-1 in the 10, 5, 2.5, 1.25 and 0.625 microgram dose groups, respectively. Increases in GMT after the booster dose were parallelled in all groups. GMT decreased by approximately equal to 65% between 7 and 12 months in the three lowest dose groups, significantly less than the fall of 80% at 5 and 10 micrograms. However, to secure variability among vaccinees, the minimum effective dose for young adults should be greater than 5 micrograms per dose.

Detection of hepatitis B virus DNA in asymptomatic hepatitis B surface antigen carriers: relation to sexual transmission.

The authors tested, by molecular hybridization, for hepatitis B virus DNA in serum specimens of 182 asymptomatic hepatitis B surface antigen (HBsAg) Greek carriers who were heterosexual partners of patients with acute hepatitis B (group A: 96 cases) or healthy subjects who were susceptible to hepatitis B (group B: 86 cases). The mean age (34.1 +/- 10.4 vs. 33.9 +/- 8.4 years) and the mean duration of sexual contact (6.9 +/- 8.9 vs. 7.2 +/- 6.3 years) were similar in the two groups of carriers. Hepatitis B virus DNA was detected significantly more frequently in group A than in group B (59.4% vs. 11.6%, p less than 0.001). In particular, in group A, hepatitis B virus DNA was detected in 96.9% of hepatitis B e antigen (HBeAg)-positive and 41% of antibody to HBeAg (anti-HBe)-positive carriers. In contrast, in group B, hepatitis B virus DNA was identified in only 10.8% of anti-HBe-positive carriers (p less than 0.001). These differences were especially significant in the young and middle-aged carriers (16-49 years old) and during the first four years of sexual contact. These data suggest that 1) there is a positive correlation between the presence of hepatitis B virus DNA in serum and the epidemiologic evidence of sexual transmission of hepatitis B virus, 2) hepatitis B virus DNA is a better indicator of infectivity than HBeAg/anti-HBe, and 3) the detection of hepatitis B virus DNA in serum probably identified carriers with high infectivity and potentially higher risk of transmitting hepatitis B virus to their sexual partners.

Natural history of acute hepatitis B surface antigen-positive hepatitis in Greek adults.

We prospectively followed up 821 adults with acute viral hepatitis hospitalized at the Athens Hospital for Infectious Diseases between May 1981 and May 1983. Radioimmunoassays for the detection of serologic markers of hepatitis A virus, hepatitis B virus, and hepatitis delta virus, and molecular hybridization techniques for the detection of serum hepatitis B virus deoxyribonucleic acid and hepatitis delta virus ribonucleic acid were used. Based on the results of an enzyme immunoassay for the detection of immunoglobulin M antibody to hepatitis B core antigen (Corzyme-M), 563 cases were diagnosed as acute hepatitis B and 45 as acute hepatitis superimposed on hepatitis B surface antigen carriage. Development of the hepatitis B surface antigen carrier state was observed in only 1 (0.2%) of the 507 cases with acute hepatitis B that were followed. In contrast, hepatitis B surface antigen persisted in all the latter cases. Acute hepatitis superimposed on hepatitis B surface antigen carriage was attributed to hepatitis A virus superinfection in 2 (4.4%), hepatitis delta virus superinfection in 22 (48.9%), reactivation of chronic type B hepatitis in 12 (26.7%), seroconversion from hepatitis B e antigen-positive to anti-hepatitis B e antibody-positive in 2 (4.4%), presumed superinfection by non-A, non-B agent(s) in 6 (13.4%), and the first clinical manifestation of chronic active hepatitis in 1 (2.2%) case. These data show that acute clinical hepatitis B in adults seems to be a self-limited disease and rarely leads to the development of the carrier state in this epidemiologic setting and hepatitis delta virus superinfection and spontaneous reactivation of chronic hepatitis B are the principal causes of acute hepatitis superimposed in hepatitis B surface antigen carriers in an area with a moderately high prevalence of hepatitis B virus infections.

Prevalence of HBV, HDV and HIV infections among intravenous drug addicts in Greece.

The prevalence of HBV, HDV and HIV infection was studied in 288 imprisoned intravenous drug addicts (IVDA) and 329 controls. Commercially available radioimmunoassays for the detection of HBV and HDV serologic markers and enzyme-immunoassays for IgM anti-HBc and anti-HIV were used. Anti-HIV positive results were confirmed by Western Blot. The prevalence of HBV serologic markers among IVDA (77.1%) was found considerably higher than among controls (22.5%). An increased prevalence of HBsAg carriers (6.9%) and anti-HBc alone positives (9.7%) was also found. IVDA carriers were more frequently HBeAg positive (25.0%) and HDV serologic markers were detected in 35.0% (7/20) of them. Anti-HIV were detected in 6 (2.1%) IVDA but in none control. These data show the widespread HBV and HDV infections among Greek IVDA and suggest the need for continuation of the initiated hepatitis B vaccination program. Anti-HIV prevalence is yet low. However there is urgent need for an extensive campaign to limit the further spread of the HIV among this high risk group.

New vaccines against hepatitis B.

The high cost and limited availability of the plasma-derived hepatitis B vaccines have prevented their widespread use, especially in the less developed areas where they are needed most. Hepatitis B vaccines produced by recombinant technology seem to offer a solution to these difficulties. Studies reported up to now confirmed the safety of this vaccine. Immunogenicity studies in various population groups showed that seroconversion rates and antibody titres are comparable to plasma vaccine. In assessing the efficacy of the vaccine, information concerning the quality of the anti-HBs induced should complement these data. Potential live vaccines using recombinant vaccinia viruses have been constructed for hepatitis B. Preliminary studies in rabbits and chimpanzees indicated the feasibility of future using a recombinant vaccinia virus. Chemically synthesized polypeptides corresponding to relevant epitopes of HBsAg may be useful as synthetic vaccines offering the advantages of a cheap viral immunogen free from irrelevant antigenic determinants. Finally preliminary studies for an idiotypic vaccine have already been reported.

An epidemic of hepatitis A in an institution for young children.

A common-source epidemic of hepatitis A occurred in an Athenian institution boarding 38 children (mean age 4.8 years). All children were examined, and blood was drawn from each at the onset of the study and repeatedly during the next three months. Only one child (2.6%) was initially immune to hepatitis A virus as a result of prior infection. The attack rate (62.2%) and the ratio of icteric to anicteric cases (1:1.3) were high despite the administration of immunoglobulin (IG). Assays for anti-HAV IgM and a rising titer of anti-HAV IgG identified 19 (82.6%) and 22 (95.7%) of the 23 hepatitis A infections, respectively. One case (4.3%) was detected only by the presence of hepatitis A virus antigen and hepatitis A virus RNA in a fecal specimen, but these assays were otherwise marginally useful in this study. Nevertheless, the use of all available tests for the detection of hepatitis A virus is mandatory for the most accurate estimation of an epidemic of hepatitis A. Prompt administration of immunoglobulin had no effect on the number of clinical cases that were in the late incubation period, but it may have diminished the clinical expression of the infection and thus made diagnosis of infection more difficult.

Fulminant hepatitis in asymptomatic hepatitis B surface antigen carriers in Greece.

Eleven male fulminant hepatitis (FH) patients (mean age: 47.7 +/- 16 years) positive for hepatitis B surface antigen (HBsAg) but negative for IgM antibody to hepatitis B core antigen (IgM anti-HBc) were admitted consecutively to the Athens Hospital for Infectious Diseases between May 1981 and November 1983. Because of the absence of IgM anti-HBc, determined by an enzyme immunoassay, these patients were considered to be HBsAg carriers with a superimposed acute hepatitis. Three of the 11 patients received immunosuppressive chemotherapy during the six months before the onset of the acute hepatitis. None of the patients was homosexual or a drug addict. Infection with hepatitis A virus (HAV), hepatitis B virus (HBV), or hepatitis delta virus (HDV) was detected with serologic markers and/or molecular hybridization techniques. Fulminant hepatitis was attributed to spontaneous reactivation of chronic hepatitis B in four patients, chemotherapy-induced reactivation of chronic hepatitis B in three patients, HDV superinfection in one patient and possible superinfection by non-A, non-B agent(s), HDV, or HDV-like agents in three patients. Reactivation of chronic hepatitis B was an important cause of apparent acute hepatitis in heterosexual male HBsAg carriers from an area with a high prevalence of HBV infection.

Significance of IgM antibody to hepatitis B core antigen in a Greek population with chronic hepatitis B virus infection.

IgM antibody to hepatitis B core antigen (IgM anti-HBc) may indicate an active immune response to persistent infection with hepatitis B virus (HBV). We studied 186 Greek HBsAg carriers for IgM anti-HBc and attempted to correlate it with other HBV and hepatitis delta virus (HDV) markers. Overall, IgM anti-HBc was detected more frequently than HBV DNA in this population (50% vs 34, p less than 0.001); this was also true for the 149 of the 186 HBsAg carriers with antibody to hepatitis B e antigen (anti-HBe) (48% vs 22%, p less than 0.001). The opposite was found in the carriers positive for hepatitis B e antigen (HBeAg): HBV DNA was observed in 93% and IgM anti-HBc in 64% of the cases (p less than 0.05). The detection of these markers was independent of sex. Serum alanine aminotransferase (ALT) levels were significantly more elevated in patients with positive tests for IgM anti-HBc and HBV DNA than in patients positive only for HBV DNA (p less than 0.001) irrespective of their HBeAg or anti-HBe status. Moreover, the detection of elevated ALT was independent of the intensity of the HBV DNA hybridization signal. Antibodies to hepatitis delta antigen (HDAg) were only found in 4 (2.4%) of 167 patients tested.

Immunogenicity of a reduced dose of recombinant hepatitis B vaccine.

We report a trial of a reduced dose (2.5 micrograms) of recombinant hepatitis B vaccine, carried out over seven months in 54 males aged 17 to 19 years. Response to the reduced dose was significantly inferior to that found in equivalent trials of 5 and 10 micrograms doses. Although all seroconverted, three participants (6%) remained below the protective level of 10 IU l-1 of antibody to hepatitis B surface antigen (anti-HBs) and a further eight (15%) below 100 IU l-1, possibly requiring early revaccination. The final geometric mean titre of anti-HBs was 810 IU l-1 (95% confidence interval, 433 to 1520). It appears that 2.5 micrograms may be too low a dosage for general use in adults.

Hepatitis B virus infection in dentists and dental students in Greece.

The prevalence of hepatitis B virus (HBV) markers in 416 dental students, 115 dentists, and 329 members of the general population was studied in Athens. Markers were present in 36 students (8.7%), 34 dentists (29.6%), and 74 controls (22.5%). Four students (1.0%), 3 dentists (2.6%), and 6 controls (1.8%) were carriers of hepatitis B surface antigen (HBsAg). The prevalence of HBV infections increased with age significantly faster in the dental profession than in the general population, showing an increased risk. Of 22 dentists in practice for more than 20 years, 12 (54.5%) had HBV markers and 4 (18.2%) reported a clinical hepatitis infection. These data show that members of the dental profession should also be included in the national hepatitis B vaccination program.

Search for hepatitis B virus DNA in sera from patients with acute type B or non-A, non-B hepatitis.

One hundred and three single sera from adults hospitalized with acute type B (78) or non-A, non-B (25) hepatitis were tested for the presence of hepatitis B virus DNA (HBV DNA). All sera from patients with type B hepatitis were IgM anti-HBc-positive. These patients were classified as benign (47) or fulminant (31) hepatitis. The 25 acute non-A, non-B patients were also classified as benign (21) or fulminant (4) hepatitis and were negative for serologic markers of past HBV infection. Serum HBV DNA was detected with similar frequency in benign (38.5%) and fulminant (FH, 34.6%) HBsAg-positive cases. HBV DNA was not detected in either the 26 acute HBsAg-negative hepatitis B cases who were positive for anti-HBc and anti-HBs or the 25 acute non-A, non-B hepatitis cases. The absence of HBV DNA in 43.8% of benign hepatitis B patients who were positive for HBsAg and HBeAg could possibly be attributed to either low level replication of HBV that was not detectable by the [32P]HBV DNA probe or to a period of delayed clearance of free HBeAg following cessation of HBV replication. Emergence of anti-HBs in the presence of HBsAg did not always correspond to clearance of HBV in fulminant type B cases. However, in acute type B hepatitis, irrespectively of severity, disappearance of HBsAg and appearance of anti-HBs was accompanied by reduction of HBV replication to undetectable levels.

Lack of antibodies to LAV/HTLV-III in hepatitis B vaccine recipients.

There is no evidence up to now that the currently available plasma hepatitis B vaccine transmits the agent of AIDS. To support further the safety of this vaccine we examined 137 vaccinees for the presence of antibodies to LAV/HTLV-III. Three groups had received Merck, Sharp and Dohme hepatitis B vaccine (two groups of 25 Air Force cadets vaccinated with investigational lots and 18 multiply transfused children vaccinated with a commercial lot); another two groups (50 Air Force cadets and 19 multiply transfused) were vaccinated with two commercial lots of Institut Pasteur vaccine. Sera were collected before inoculation, 7 and 24 months later. Enzyme linked immunosorbent assay was used for the detection of antibodies to LAV/HTLV-III. Positive sera were tested again by Western Blot and Radioimmune Precipitation Assay to exclude non-specific binding. Antibodies to LAV/HTLV-III were not detected in any of the sera examined, providing evidence for safety. We believe that these data increase the acceptance of hepatitis B vaccine.

Double infections with hepatitis A and B viruses.

Ten (2.8%) asymptomatic carriers of HBsAg and four (1.1%) patients with acute hepatitis B virus (HBV) infection were detected among 356 adults with acute viral hepatitis A (HAV) consecutively admitted to the Athens Hospital for Infectious Diseases from May 1981 to March 1984. These patients did not differ in clinical, epidemiologic (except in age), biochemical or serologic characteristics from patients acutely infected with HAV alone. Transient suppression of the HBV replication and disappearance of the HBV DNA accompanied by seroconversion from HBeAg positive to anti-HBe positive were detected in one and two carriers respectively. The titer of non-class-specific anti-HBc was low (less than or equal to 10(-2)) in all cases. These data suggest that superinfection of HBsAg carriers with HAV does not cause more severe disease or influence adversely the course of chronic hepatitis B disease. However, accurate diagnosis of double infections is necessary for prognosis of the liver disease and appropriate management of the patient's environment. This is quite important in areas with a high prevalence of HBV infections, like Greece, where double infections are relatively common.