Long-term persistence of anti-HBs after vaccination with a recombinant DNA yeast-derived hepatitis B vaccine: 8-year results

The aim of this study was to evaluate the persistence of antibodies 7 years after hepatitis B booster administration in healthy adult volunteers who were vaccinated in 1986. In October 1986, 188 seronegative, healthy adult volunteers (117 men and 71 women) were vaccinated with a 20 micrograms dose recombinant DNA yeast-derived hepatitis B vaccine. Mean age of the study group was 23.3 years (+/- 0.28). Immunisation was carried out according to a 0-1-2 month vaccination schedule, with a booster dose at 12 months. Of the 159 subjects who received the full vaccination course, 63 (40%) had a blood sample taken 8 years after the first vaccination. Of these 63 subjects, five were excluded from the analysis due to an irregular vaccination schedule and four subjects did not complete the accompanying questionnaire on possible booster administration. So, 54 subjects remained available for further analysis. Fourteen individuals had received an additional booster of hepatitis B vaccine sometime between 1989 and 1994. The geometric mean titre (GMT) at month 13 for these 14 individuals was 1494 mIU ml-1, compared with 3103 mIU ml-1 for those who did not receive an interim booster. Forty subjects, who received no additional booster dose besides that of month 12, met the inclusion criteria of the follow-up study. Of these, all subjects except one were seropositive for anti-HBs at month 96 (GMT: 215.9 mIU ml-1). All subjects were still anti-HBc negative at that time. Distribution of individual antibody titres revealed that overall 92.5% of subjects retained protective antibody levels (> or = 10 mIU ml-1); 72.5% of vaccinees retained high levels of anti-HBs (> or = 100 mIU ml-1) as compared to 99.2 and 97.0% at month 13, respectively. A positive correlation was found between the subjects' titres at month 13 and month 96. A 0-1-2 dose vaccination course with a booster dose administered at month 12, induces a protective immune response which lasts at least until 7 years after the full vaccination course of the subjects. A positive correlation was found between the anti-HBs antibody titres at month 13 and month 96.     

Comparison of immunogenicity of vaccination and serovaccination against hepatitis B virus in patients with alcoholic cirrhosis

OBJECTIVES: The association of anti-HBs immunoglobulins and anti-HBV vaccine could increase the immunogenicity of the latter. The aim of this prospective randomized trial was to compare the immunogenicity of anti-HBs vaccination and serovaccination in alcoholic patients with cirrhosis. METHODS: Alcoholic patients with cirrhosis were randomized in 2 groups: a) Vaccination group: 3 i.m. injections of GenHevac B followed by one booster at month 9; b) Serovaccination group: same vaccination schedule followed by one i.m. injection of anti-HBs immunoglobulins (500 IU). RESULTS: Twenty-five patients (17 males and 8 females, mean age 56 years) were included in the study: 13 received a vaccination and 12 received a serovaccination. After 12 months, the seroconversion rates were 69% and 67% in vaccination and in serovaccination groups, respectively. The predictive factors of non responsiveness were as following: Child B cirrhosis, low number of CD8, a high CD4/CD8 rate, the existence of HLA DR7 antigen, and the absence of HLA DR1 antigen. CONCLUSION: In alcoholic patients with cirrhosis, serovaccination does not increase the immunogenicity of anti-HBs vaccination and should not be recommended.     

Access to a three-dimensional measure of vertebral axial rotation

BACKGROUND: A combined diphtheria-tetanus-whole cell pertussis-hepatitis B (DTPwHB) vaccine might facilitate the achievement of universal vaccination of infants against hepatitis B. METHODS: A double blind, randomized, two-armed, single center study was undertaken to evaluate the immunogenicity and reactogenicity of combined tetravalent DTPwHB vaccine, with two dosages of hepatitis B component (10 microg and 5 microg). The combined vaccine was tested in the context of a simplified vaccination schedule at 1.5, 3.5 and 6 months of age, to 120 healthy infants born to hepatitis B surface antigen-negative mothers after priming with one dose of hepatitis B vaccine (10 microg) at birth. Antibodies to each antigenic component were measured from blood samples collected immediately after birth, pre- and postvaccination blood samples. RESULTS: The reactogenicity profiles were similar in the two groups. No serious adverse events were reported. One month after completion of the four-dose vaccination schedule, all subjects except one in Group 1 (10 microg) had protective titers of anti-HBs (10 mIU/ml). At this time the geometric mean titer in Group 1 (10 microg) was higher than that observed in Group 2 (5 microg), 696 vs. 488 mIU/ml (P = 0.19). One month after three doses all subjects in both groups had protective antidiphtheria titers and antitetanus titers. The vaccine response rate to the Bordetella pertussis component of the vaccine was 88.0% in Group 1 and 96.2% in Group 2 (P = 0.86). CONCLUSION: Both combined tetravalent vaccines are safe and immunogenic when administered to infants born to a hepatitis B surface antigen-negative mother, with a 10-microg dose of priming hepatitis B vaccine at birth. This combined tetravalent DTPwHB vaccine may play an important role to promote integration of HB vaccine into the Expanded Program of Immunization in hepatitis B-endemic areas.     

Risk factors for lack of detectable antibody following hepatitis B vaccination of Minnesota health care workers

OBJECTIVE: To assess the presence of antibody to hepatitis B surface antigen (anti-HBs) at postvaccination testing in Minnesota health care workers receiving recombinant hepatitis B vaccines, and to identify risk factors for lacking anti-HBs following hepatitis B vaccination. DESIGN: Retrospective cohort study. SETTING: Ten acute care hospitals in Minnesota. PARTICIPANTS: A total of 595 health care workers who had received hepatitis B vaccine (Recombivax HB or Engerix-B) between June 1987 and December 1991 and who underwent postvaccination testing for anti-HBs within 6 months after receiving the third dose of vaccine. MAIN OUTCOME MEASURE: Presence or absence of anti-HBs following hepatitis B vaccination. RESULTS: Five variables were independently associated with lacking anti-HBs by multivariate analysis: vaccine brand, smoking status, gender, age, and body mass index. Stratifying by vaccine brand demonstrated that age (P = .01), body mass index (P < .01), and smoking status (P < .01) were associated with lacking anti-HBs only for Recombivax HB recipients; and gender (P = .03) was associated with lacking anti-HBs only for Engerix-B recipients. After controlling for smoking status, age, gender, and body mass index, recipients of Recombivax HB were more likely to lack anti-HBs than recipients of Engerix-B (relative risk, 2.3; 95% confidence interval, 1.1 to 4.7; P = .02). CONCLUSIONS: Results indicate that certain populations of health care workers are at increased risk of not responding to hepatitis B vaccination. Further studies evaluating immunogenicity of currently available recombinant hepatitis B vaccines in persons at high risk for primary vaccine failure are needed.     

Ogura and Powers: "Functional restitution of traumatic stenosis of the larynx and pharynx." (Laryngoscope 1964;74: 1081-1110)

The objective of this study was to evaluate the immune response and reactogenicity of a combined hepatitis B, diphtheria, tetanus and whole-cell Bordetella pertussis (DTPw-HBV) vaccine administered to healthy infants at 2, 4 and 6 months of age. A total of 179 infants (6-12 weeks of age) received three doses of DTPw-HBV vaccine. Blood samples for antibody determinations were taken before vaccination, 2 months after the second dose and 1 month after the third dose. Solicited and unsolicited symptoms were recorded by parents in a diary card. All vaccinees had protective levels of anti-HBs [geometric mean titre (GMT): 1526 mIU.ml-1], anti-diphtheria and anti-tetanus antibodies, 1 month after the third dose. Ninety-two percent of the subjects exhibited a response to the B. pertussis component. Most (99.4%) solicited reactions occurred within the first 48 h and the majority were mild or moderate. The safety, immunogenicity of this tetravalent vaccine was demonstrated when it was administered in infants following the 0, 2, 4-month dosing schedule.     

Evolutional neurologic evaluation of seven year-old children born prematurely

Personnel (1856 subjects) belonging to local health units (medical and paramedical staff) that have been vaccinated since 1984 against hepatitis B virus (HBV) with HBsAg plasma purified preparations (Hevac-B and H-B-Vax) or recombinant DNA preparation (Engerix-B) were followed in plasma anti-HBs antibody levels. At the end of the protocols, different seroconversion percentages and different anti-HBs levels were reached: the best results were obtained with Engerix-B. Sex and principally age influenced the antibody production: women generally reached highest protective antibody levels and the 21-30 year group was more responsive than other groups. The injection of a supplementary 4th or 5th dose in low or non-responders could restore the specific immunity in the majority of the subjects and increase the anti-HBs level. The time course after the immunization of antibody levels depended on the level reached at the end of vaccination schedule. These data suggest that different antibody level monitorings of vaccinated subjects, planned on the basis of the antibody level reached at the end of vaccination, could prevent a loss of protection against the HBV infection.     

Antenatal diagnosis of esophageal atresia with tracheoesophageal fistula

We have studied the antibody response to hepatitis B vaccine in 42 hemodialysis patients; 8 of them were diagnosed as having HCV infection before vaccination. Hemodialysis patients received four doses of recombinant HB vaccine (Engerix-B, SKB, 40 micrograms per dose). Seroconversion occurred in 71.4% of all hemodialysis patients; in 79.4% of HCV-negative and in 37.5% of HCV-positive patients. Effective immunity (anti-HBs titer higher than 100 m IU/ml) was observed in 12.5% of HCV positive and in 35.3% of HCV-negative patients. We conclude that HCV infection may modify or postpone the response to hepatitis B vaccine.     

The abbreviated 2-1-1 schedule of purified chick embryo cell rabies vaccination for rabies postexposure treatment

During August 1988 to January 1990, the immunogenicity and safety of purified chick embryo cell rabies vaccine (PCEC) given by the conventional and abbreviated regimens in 82 vaccinees moderately to severely exposed to laboratory proven rabid animals were studied. The 16 vaccinees received PCEC six doses as conventional schedule on days 0, 3, 7, 14, 28 and 90, the 11 vaccinees received six doses of PCEC plus human rabies immune globulin (HRIG) on day 0. The 29 vaccinees received an abbreviated schedule of PCEC as two doses on day 0, one dose each on days 7 and 21 and the 26 cases received PCEC abbreviated schedule plus HRIG on day 0. The kinetics of the neutralizing antibodies on days 0, 7, 14, 28, 56, 180 and 365 were studied for comparative purpose. All vaccinees had high antibody levels from day 14 which last longer than a year and were safe after one year follow up. The adverse reactions of the vaccine were mild and self-limited.     

Immune status in preschool children born after mass hepatitis B vaccination program in Taiwan

A mass hepatitis B vaccination program began in Taiwan in 1984. In order to determine the immune status of hepatitis B virus (HBV) infection among preschool children, a total of 25 kindergartens in 20 townships and metropolitan precincts in central Taiwan were randomly selected through stratified sampling. Serum specimens of 2130 healthy preschool children aged 2-6 years old were screened for the HBV markers and liver function in 1996. HBV surface antigen (HBsAg), antibody against HBsAg (anti-HBs) and antibody against HBV core antigen (anti-HBc) were tested by reverse passive hemagglutination (RPHA), enzyme immunoassay (EIA) and radioimmunoassay (RIA) using commercial kits. HBV vaccination rate of the preschool children was 98%, and complete vaccination rate (three or four doses of HBV vaccine) was 94%. The HBsAg seropositive rate was 4.5% among incomplete vaccinees and 1.3% among complete vaccinees. The anti-HBs was detectable in 1637 of 2000 complete vaccinees (81.9%) and in 53 of 88 incomplete vaccinees (60.2%). The overall prevalence rate of anti-HBc was 2.4% (52 of 2130). The older the age, the lower the anti-HBs seropositive rate. The anti-HBs seropositive rats for complete vaccinees were 100% at 2 years old and 75% at 6 years old. There were no significant differences in HBsAg-seropositive rates and anti-HBs-seropositive rates among different residential areas or ethnic groups. There were three children who were seropositive on HBsAg, anti-HBs and anti-HBc, whether they were infected by the vaccine-induced escape mutant of HBV deserves scrutiny.     

Hepatitis B component does not interfere with the immune response to diphtheria, tetanus and whole-cell Bordetella pertussis components of a quadrivalent (DTPw-HB) vaccine: a controlled trial in healthy infants

The aim of this single-blind, parallel trial was to assess whether the hepatitis B (HB) component of a DTPw-HB vaccine interferes with the immune response to the other three components when administered at 3, 5 and 7 months of age. One hundred and six infants were randomized to receive three doses of DTPw or DTPw-HB vaccines. Seroprotection (or seroresponse) rates and geometric mean titers (GMT) of antibodies were assessed 3-6 weeks after the third dose. Anti-diphtheria, anti-tetanus and anti-Bordetella pertussis antibodies were measured by ELISA and anti-HBs by radioimmunoassay. Local and general signs and symptoms were recorded for a 4-day follow-up period after each vaccination. After the full vaccination course all subjects in both groups had seroprotective titers (> or = 0.1 IU ml-1) against diphtheria and tetanus and seroresponded (titers > or = 15 EL.U ml-1) to B. pertussis, and there was no significant difference between groups in relation to GMT. All subjects vaccinated with DTPw-HB had seroprotective levels (> or = 10 mIU ml-1) of anti-HBs antibodies after the third dose (GMT of 2318 mIU ml-1). Overall there were no significant differences between groups in relation to the incidence of local and general symptoms. These results show that the HB component did not interfere with the immune response to the other three components of the vaccine.     

Randomized comparison of early and late vaccination with inactivated poliovirus vaccine after allogeneic BMT

Forty-five adult HLA-matched sibling BMT recipients were randomized to receive inactivated poliovirus vaccine (IPV) at 6, 8 and 14 months (early group, n = 23) or at 18, 20 and 26 months after BMT (late group, n = 22). Ninety-five percent of the early group patients had protective antibody titres of > or = 4 to poliovirus type 1 (PV1), poliovirus type 2 (PV2) and poliovirus type 3 (PV3) by a microneutralization assay prior to the first vaccination, at 6 months after BMT. The corresponding proportion for the late group patients was only 67% at 18 months. The antibody responses 1 month after each of the three IPV doses were similar in the two vaccination groups, except that four-fold responses occurred more frequently after the first dose to PV2 and PV3 in the late group. All patients had a protective antibody titre to all poliovirus serotypes 1 and 22 months after the third vaccine dose, except one patient in the early group who lacked antibodies to PV3 at 22 months. Acute GVHD accelerated the decrease of poliovirus antibody titres prior to vaccination but had no influence on vaccination response. Chronic GVHD neither influenced the patient's ability to retain poliovirus antibodies prior to vaccination nor impaired responses to vaccinations. A vaccination schedule consisting of three IPV doses was equally immunogenic when started at 6 or 18 months after allogeneic BMT.     

Juvenile offenders and hepatitis B: risk, vaccine uptake and vaccination status

OBJECTIVE: To determine the hepatitis B vaccination status of juvenile offenders in a custodial setting, their perceived risk of hepatitis B infection, and factors influencing vaccine uptake. DESIGN: 130 males aged 14-17 years resident at the Melbourne Juvenile Justice Centre for at least one week between mid-January and mid-December 1996 were invited to participate; 90 (69%) completed a doctor-administered questionnaire, and blood for serological testing was obtained from 83 of these participants. MAIN OUTCOME MEASURES: Whether hepatitis B vaccine had been offered; whether hepatitis B vaccine had been given; the presence of antibodies to hepatitis B and C; risk factors and self-perceived risk of hepatitis B. RESULTS: About a quarter of participants (22/83) had protective levels of antibody to hepatitis B surface antigen (anti-HBs). Forty (44%) participants reported having been offered hepatitis B vaccine; they were more likely to be vaccinated and have protective levels of anti-HBs. Perceived risk for bloodborne virus infection was low, although two-thirds of participants were at high risk of hepatitis B infection. On serological testing, 6.4% (5/78) were positive for antibody to hepatitis B core antigen (anti-HBc), and a further 2.6% (2) had equivocal antibody levels. Of the 71 who were negative for anti-HBc, 51 (71.8%) were negative for anti-HBs. CONCLUSIONS: The targeted hepatitis B vaccination program has not adequately protected this group at high lifetime risk of hepatitis B. Failure to deliver vaccine may reflect lack of contact with healthcare services, oversight in offering vaccine and reluctance of youth to participate in preventive healthcare measures, often through not seeing themselves to be at risk. Universal approaches to vaccination may be more successful in vaccinating this group.     

Hepatitis B vaccination in preterm infants

AIM: To investigate the immunogenicity and safety of existing recommendations for hepatitis B vaccination in preterm infants. METHODS: Recombinant hepatitis B vaccine (H-B-VAX II, 5 micrograms per dose) was given to 85 preterm infants divided into two groups, using two different schedules. Forty four group A infants with birthweights of < 2000 g received three doses at 1, 2, and 7 months of age. Forty one group B infants with birthweights of > or = 2000 g received three doses at 0, 1, and 6 months of age. RESULTS: After vaccination, 42 infants from group A (95%) and 37 infants from group B (90%) developed protective levels of antibody. The final seropositive rate and the geometric mean concentration of hepatitis B surface antibody between the two groups were not significantly different. The immune response of preterm infants to hepatitis B vaccines was similar to that of term infants in a previous study. CONCLUSIONS: Preterm infants can be given hepatitis B vaccines using one of the above two different schedules, at a cutoff birthweight of 2000 g.     

The direction of bladder displacement by adnexal masses

BACKGROUND: Vaccination against the hepatitis B virus (HBV) of health care staff during their studies would have the advantage of early prevention when the prevalence of infection is presumably low. METHODS: The population to be protected is made up of 1533 medical and nursing students. In those who accepted, anti-HBc was determined and information was obtained concerning circumstances of exposure to HBV. Vaccination was offered to all the cases of negative anti-HBc. Individuals receiving 3 doses of the vaccination (20 micrograms at 0, 1 and 6 months) were seen at 4-7 months of the last dose to determine the anti-HBs titers achieved. RESULTS: One thousand sixty-five students (70%) accepted inclusion into the prevaccination anti-HBc study and 1,029 (3.4%) were anti-HBc negative. Only older age and previous transfusions and jaundice were significantly associated to greater prevalence of infection by HBV. The adherence to 1, 2 or 3 doses of the vaccination was 96%, 94% and 87%, respectively. Following the 3 doses, > or = 10 UI/I of anti-HBs were detected in 97% of the cases studied with geometric measurement of the responders being 1580 U/I. The titer had an inverse relation which was not significant with age. CONCLUSIONS: The high participation in the program of anti-hepatitis B vaccination and the excellent immune response observed leads to the recommendation of systemic vaccination to future health care professionals during their study period. Furthermore, the low prevalence of previous HBV infection advises against previous detection of anti-HBc with immunization of the whole collective being more effective.     

Assessment of the immunogenicity and reactogenicity of a quadrivalent diphtheria, tetanus, acellular pertussis and hepatitis B (DTPa-HBV) vaccine administered in a single injection with Haemophilus influenzae type b conjugate vaccine, to infants at 2, 4 and 6 months of age

This double-blind, randomised study was performed to assess the immunogenicity and reactogenicity of three lots of a quadrivalent diphtheria-tetanus-acellular pertussis-hepatitis B vaccine (DTPa-HBV) co-administered with three lots of Haemophilus influenzae type b conjugate (Hib) vaccine in one injection, as a primary vaccination course in healthy infants at 2, 4 and 6 months of age. 269 infants (8-11 weeks of age) were randomly allocated to three groups to receive DTPa-HBV/Hib vaccines, concomitantly with oral polio vaccine. Blood samples for antibody determinations were taken before vaccination and 1 month after the third dose in 262 subjects. Local and general symptoms were recorded by parents on diary cards. All vaccinees had post-vaccination protective anti-D and anti-T (> or = 0.1 IU ml-1) antibodies, and 98% had protective anti-HBs antibody titres (> or = 10 mIU ml-1). There were no statistically significant differences between groups in post-vaccination anti-D, anti-T, anti-HBs antibody geometric mean titres (GMT), these being 3.49 IU ml-1, 5.92 IU ml-1 and 1109 mIU ml-1, respectively. All subjects responded to three pertussis components, i.e. pertussis toxin (PT), filamentous haemagglutinin (FHA) and pertactin (PRN). Although statistically significant differences in GMTs of anti-PT, anti-FHA and anti-PRN were found between groups, these were not believed to be of any clinical relevance as the minimum GMTs were 60, 193 and 230 EL.U ml-1 for anti-PT, anti-FHA and anti-PRN, respectively. There were no statistically significant differences in anti-PRP antibody GMT (4.05 micrograms ml-1) between groups, 100% and 85% of subjects having titres > or = 0.15 and 1.0 microgram ml-1, respectively. No symptoms were reported for one third of the subjects. Fever (> 38 degrees C) was reported after 16% of doses, with < 1% having > 39.5 degrees C. Almost all local and general symptoms were mild or moderate, and lasted less than 48 h. No subject dropped out due to a severe adverse reaction. The administration of an experimental mix of DTPa-HBV and Hib vaccines in a single injection is safe, well-tolerated and immunogenic for all vaccine components.     

Suboptimal response following intradermal hepatitis B vaccine in infants

Two hundred and twenty-five infants were randomly assigned to receive 2 micrograms of plasma-derived hepatitis B vaccine (Heptavax) intradermally (ID-2), 10 micrograms intramuscularly (IM-10), or 2 micrograms intramuscularly (IM-2) in the deltoid region at birth, 2 and 4 months. At 6 months, ID-2 infants were less likely to have developed > or = 10 mIU ml-1 of antibody to hepatitis B surface antigen (anti-HBs) than IM-10 infants (91 versus 100%; p = 0.02) and had a lower geometric mean concentration of anti-HBs (312 mIU ml-1 versus 2248 mIU ml-1; p < 0.01). At 6 months IM-10 infants had significantly lower mean weights and lengths than infants receiving 2 micrograms doses of vaccine. Intramuscular administration of 2 micrograms and 10 micrograms doses of Heptavax in the deltoid of young infants was well tolerated and effective; however, intradermal administration of Heptavax provided no immunological benefit over intramuscular administration and resulted in significantly higher rates of induration and persistent hyperpigmentation. Intramuscular immunization at birth, 2 and 4 months is an acceptable, effective alternative schedule for immunizing infants.     

Long-term efficacy and immune responses following immunization with the RTS,S malaria vaccine

The malaria sporozoite vaccine candidate RTS,S, formulated with an oil-in-water emulsion plus the immunostimulants monophosphoryl lipid A and the saponin derivative QS21 (vaccine 3), recently showed superior efficacy over two other experimental formulations. Immunized volunteers were followed to determine the duration of protective immune responses. Antibody levels decreased to between one-third and one-half of peak values 6 months after the last dose of vaccine. T cell proliferation and interferon-gamma production in vitro were observed in response to RTS,S or hepatitis B surface antigen. Seven previously protected volunteers received sporozoite challenge, and 2 remained protected (1/1 for vaccine 1, 0/1 for vaccine 2, and 1/5 for vaccine 3). The prepatent period was 10.8 days for the control group and 13.2 days for the vaccinees (P < .01). Immune responses did not correlate with protection. Further optimization in vaccine composition and/or immunization schedule will be required to induce longer-lasting protective immunity.     

Comparison of multiple immunization schedules for Haemophilus influenzae type b-conjugate and tetanus toxoid vaccines following bone marrow transplantation

Antibody concentrations to vaccine-preventable diseases decline following BMT and an optimal schedule for vaccination after transplant has not been established. We examined antibody responses to tetanus toxoid (TT) and Haemophilus influenzae type b-conjugate (HIB) vaccines of BMT patients immunized at 6, 12 and 24 months (6 month group, n = 21) and compared them to those previously reported for patients immunized at 3, 6, 12 and 24 months (3 month group, n = 74) or at 12 and 24 months (12 month group, n = 17) following transplantation. Geometric mean total anti-HIB and IgG anti-TT concentrations were significantly higher after the 12 month dose in the 3 and 6 month immunization groups compared to the group who received their first dose at 12 months. Although HIB antibody concentrations were higher in the 3 month and 6 month groups 12 to 24 months after BMT, the proportion of patients with protective levels was not significantly different from the proportion protected in the 12 month group. Following the 24 month immunizations, geometric mean antibody concentrations to HIB and TT were similar for all three immunization groups. The proportion of patients in each group with protective levels of HIB antibody after the 24 month dose was > or = 80%. A two dose schedule of HIB and TT vaccines at 12 and 24 months after BMT should afford protection.     

Comparative genotoxicity of halogenated acetic acids found in drinking water

20 years after the introduction of the hepatitis-B vaccine the question still remains unsolved as to how the 2 to 5 per cent of the vaccinees who, after basic immunisation, respond with no anti-HBs levels (0-10 IU/l nonresponder, NR) or low levels (11-99 IU/l low-responder, LR) should be boostered to acquire sufficient and long-lasting protective anti-HBs levels. In a retrospective analysis of booster results we found in 75 NR and LR that the probability for long-lasting protection is very low for NR, but better for LR (60%). In a second part of this publication, the efficacy of intradermal and intramuscular hepatitis-B boosters was examined by retrospective analysis of booster results among 26 NR and LR. A slight advantage of the intradermal application was found concerning post-booster anti-HBs increase and the maximal HBs values reached. Long-lasting protective anti-HBs values could not be established for either way of application. Finally, a survey of the literature summing up true results of intradermal hepatitis-B basic immunisations with reduced doses (mostly 2 micrograms), shows that whereas the seroconversion rates achieved by this method are almost compatible with those after regular basic vaccination, the GMT values were far lower than those after regular basic vaccination. Prospective and randomised studies are needed to show which kind of booster is most efficient for nonresponders and low-responders.