Active immunization of homosexual men using a recombinant hepatitis B vaccine

Twenty homosexual men [13 anti-human immunodeficiency virus (HIV)-positive, seven anti-HIV negative] without HBsAg, anti-HBs, and anti-HBc were vaccinated with three 20 micrograms doses of a recombinant hepatitis B vaccine. All anti-HIV-positive homosexuals were nonresponders independent of the initial number of CD4-positive cells. Among seven anti-HIV-negative individuals, five responded. After three doses of the vaccine, CD4-positive cells fell in anti-HIV positive individuals by 22.4%. A similar fall in CD4-positive cells of an average 24.9% was noted in 17 matching, but nonvaccinated, anti-HIV-positive homosexuals. The study indicates that the efficacy of vaccination in anti-HIV-positive individuals is questionable. There is, however, no evidence that vaccination against hepatitis B might be harmful to anti-HIV-positive subjects.     

Syphilis,hepatitis A and hepatitis B seromarkers in homosexual men

Summary Two hundred homosexual men were investigated for prevalence rates of syphilis, hepatitis A (HAV) and hepatitis B (HBV). A reactive Treponema pallidum haemagglutination test (TPHA) was found in 56.3% of the participants. In 81.7% HBV scromarkers were detected. Hepatitis B surface antigen (HBsAg) was present in 6.6%. Anti-HAV was found in 51.0%. Risk factors for acquisition of these infections are discussed.     

Long-term serologic follow-up of hepatitis C virus-seropositive homosexual men.

Hepatitis C virus (HCV) infection may go undiagnosed and continue to present a source of community-acquired or transfusion-associated infection because of shortcomings in sensitivity, specificity, and reproducibility of serologic tests. This project was designed to longitudinally study persons who were HCV seropositive or were at risk for seroconversion to characterize the course of infection. Sequential serum samples obtained semiannually from 617 homosexual male volunteers were available for study from the Pittsburgh site of the Multicenter AIDS Cohort Study. Testing by anti-HCV enzyme immunoassay (EIA) was performed on baseline (1984 to 1985) and most-recent (censor date, August 1992) samples. Selected samples were also assayed for alanine aminotransferase and by recombinant immunoblot (RIBA II) and nested PCR. A total of 17 of 617 (2.8%) men were HCV seropositive at entry. Of the 600 seronegative men, 9 converted to HCV seropositive during the study interval. Parenteral sources of exposure could be identified in 6 of these 26 HCV-seropositive men. Four men were HCV seropositive at baseline and seronegative at their most recent visit. Of the 26 HCV-seropositive men, 12 were also seropositive for human immunodeficiency virus. EIA analysis of 298 longitudinal samples from the 26 men revealed three patterns of HCV seropositivity: persistent, intermittent, and rare. Nine men (35%) showed intermittent or rare seropositivity with periods of over 1 year between some seropositive samples. PCR was positive in 76% of the HCV EIA-positive and 84% of the RIBA-positive samples. Thus, a low but significant number of homosexual men were HCV seropositive with variable positivity over several years of follow-up. A portion of these men become HCV seronegative. Individuals who exhibit intermittent or rare seropositivity are a challenge to diagnosis.     

Long-term immunogenicity of an inactivated virosome hepatitis A vaccine

The aim of this study was to predict the long-term protection induced after immunisation with inactivated, aluminium-free virosome hepatitis A vaccine. The study population consisted of adult volunteers enrolled in four different clinical trials. Lower 95% confidence interval limits and seroconversion rate were calculated by using a linear mixed model to estimate the persistence of serum antibodies over time. To assess the robustness of the mathematical model, several sensitivity analyses were performed with more conservative protective threshold (20 mIU/ml vs. 10 mIU/ml), higher yearly decline rate, and exclusion of volunteers who had increasing titres over time. Based on 190 volunteers with at least two valid assessments of titres from year 3 onward, the median duration of protection was 55.5 years, with a lower limit of the 95% CI of 48.7 years. Duration below 25.3 years was predicted for only 5% of the subjects. Women tended to have higher titres to start with, but their rate of decline was higher, resulting in similar duration of protection overall. The use of a more conservative threshold, higher yearly decline rate, and exclusion of volunteers with increasing titres over time did not affect these results. According to this model, 95% of the volunteers should have anti-HAV titres above the minimum protective threshold for 20 years or more following immunisation with two doses of this aluminium-free vaccine.     

Safety and immunogenicity of a recombinant hepatitis B vaccine

A hepatitis B vaccine produced in yeast by recombinant DNA technology was evaluated using 5-micrograms and 10-micrograms doses in a randomized trial lasting 7 months in 110 male armed forces recruits aged 17-19 years. Results were compared to those of an identical trial of a plasma-derived vaccine. No allergic reactions were observed, and the rate of mild side effects was similar to the plasma-derived vaccine. Seroconversion rates in the first month were 60% (33/55) and 67% (37/55) with the 5-micrograms and 10-micrograms doses of the recombinant vaccine, respectively. All participants seroconverted by 3 months, and none lost antibody. These results are very similar to those for plasma-derived vaccine. Comparison of titres of antibody to hepatitis B surface antigen (anti-HBs) showed a slightly higher level with the 10-micrograms than with the 5-micrograms dose of the recombinant vaccine. Geometric mean titres of anti-HBs after the booster dose were similar in the 5-micrograms and 10-micrograms dose recombinant vaccine groups (2,620 and 2,748 IU/l, respectively) and in the 5-micrograms plasma-derived vaccine group (3,591 IU/l) but significantly higher (9,227 IU/l) with the 10-micrograms dose of the plasma-derived vaccine. These results confirm the safety and immunogenicity of the recombinant vaccine, although further study is needed on the duration of immunity.     

A review of the efficacy, immunogenicity and tolerability of a combined hepatitis A and B vaccine

Hepatitis A and B are two of the most common vaccine-preventable liver diseases and continue to be a significant cause of morbidity and mortality worldwide, with their severity related to the individual's age upon initial infection. Twinrix (GlaxoSmithKline), a combined vaccine providing protection against both hepatitis A and B, has been available in more than 72 countries worldwide since 1997. This paper provides a critical review of clinical data on the efficacy, immunogenicity and tolerability of the combined vaccine, with particular focus on the clinical benefits of dual vaccination.     

Field evaluation of the efficacy and immunogenicity of recombinant hepatitis B vaccine without HBIG in newborn Vietnamese infants

A study involving more than 2,000 infants was conducted in Vietnam to assess the field effectiveness and immunogenicity of recombinant hepatitis B vaccine given at birth, 1 month, 2 months, without concomitant hepatitis B immune globulin (HBIG). All received a 5 microg dose of H-B-VAX II at birth. Infants born to non-carrier mothers (Group 1; N = 1798) then received 2.5 microg doses at 1 and 2 months of age, while infants of HBeAg-negative (Group 2; N = 125) or HBeAg-positive (Group 3; N = 88) carrier mothers received 5 microg doses. No Group 1 or 2 vaccinees were infected. In Group 3, 12 (14.6%) of 82 infants did become infected (estimated efficacy 84%). 98.0-98.6% of uninfected infants who were tested for anti-HBs developed a seroprotective concentration > or = 10 IU/L. In hyperendemic Vietnam, where routine maternal screening and passive-active prophylaxis of high-risk infants with vaccine plus HBIG is not feasible, administration of vaccine alone to all newborns may control effectively HBV infection.     

Diminished response to recombinant hepatitis B vaccine in homosexual men with HIV antibody: an indicator of poor prognosis

Three doses of a recombinant DNA HBV vaccine (MSD) were given to healthy male homosexuals. Seventy-eight out of 104 (77.6%) participants had detectable antibody (anti-HBs) two months after the third dose. Seroconversion occurred in only 9 out of 27 subjects (33.3%) who were anti-HIV positive compared with 69 out of 77 (89.6%) who were negative (chi 2 = 30.8; P less than .001). Fifteen of the 18 anti-HIV positive who did not mount an antibody response to the hepatitis B vaccine (anti-HBs) later progressed to persistent generalised lymphadenopathy syndrome (5), AIDS-related complex (5), and AIDS (5). Only one of the nine anti-HIV positive anti-HBs responders developed PGL (chi 2 = 10.14; P less than .005). Our results show that anti-HIV positive homosexuals are poor responders to the recombinant hepatitis B vaccine and anti-HIV positive non-responders are more likely to develop clinically apparent HIV infection.     

Specific safety and immunogenicity of a subunit vaccine against hepatitis B

The results of trials of a subunit vaccine against hepatitis B in volunteers are presented. The active substance of the vaccine was HBsAg isolated from the plasma of asymptomatic antigen carriers. The preparation under study is highly immunogenic, shows poor reactogenicity, and safety in use.     

Reactivity and immunogenicity of Engerix B, the recombinant DNA vaccine against hepatitis B

A group of 67 health workers with no markers indicating previous hepatitis B infection were vaccinated against hepatitis B with a new DNA recombinant vaccine, Engerix B (commercially manufactured by Smith-Kline-RIT, Belgium). Three injections were given according to the 0-1-6 schedule. One month after the last injection the vaccinees were tested for anti-HBs antibodies by the enzyme-linked assay. Antibody titers equal or less than 10 mIU/ml were found only in three subjects or in 4.5% of them. Titers ranging from 11 to 99 mIU/ml were found in 7 subjects (10.4%), from 100 to 999 mIU/ml in 28 (41.8%) and those equal or more than 1000 mIU/ml in 29 subjects (43.3%). It is inferred that the seroconversion rate is 95.5%. Only one subject did not develop detectable antibodies but three subjects had titers over 10000 mIU/ml. No one developed overt hepatitis B during the trial nor did the high responders experienced inapparent infections. They were tested for anti HBc with negative results. Postvaccinal reactions were mild and almost exclusively local. There were no complications. For its high immunogenicity and acceptable reactogenicity the Engerix B vaccine has a promising future.     

Active pre-exposure immunisation against hepatitis B virus: immunogenicity of hepatitis B vaccine in healthy Thai adults and children

The immunogenicity of plasma derived hepatitis B vaccine (Hevac B) was studied for active pre-exposure immunisation in 176 healthy volunteer adults and 162 randomised children who had no hepatitis B virus markers. All subjects received three injections of 5 micrograms of hepatitis B vaccine intramuscularly at one month intervals. Seroconversion at 2 months after the third dose of vaccine was 96.30 percent in the children and 92.00 percent in the adults with mean anti-HBs titres of 800 mlU/ml and 353 mlU/ml respectively. The difference of anti-HBs levels between these two groups was statistically significant (p less than 0.05). Female adults had exhibited higher immune response to HB vaccine than male adults but there was no seroconversion difference between boys and girls. There were no serious local or systemic side effects of hepatitis B vaccination. It was concluded that active immunisation with plasma derived hepatitis B vaccine in non-immune children and adults is highly effective without any serious side effects or complications. The prevention of horizontal transmission of hepatitis B virus should be done by vaccination in children since they have a much better immune response to hepatitis B vaccine than adults.     

基因工程乙型肝炎疫苗免疫原性和免疫效果的评价

80年代第一个基因工程疫苗———乙肝疫苗研制成功 ,以后随着对目的基因选择、抗原表达系统、质量评价等方面的研究进展 ,对其质量问题产生了不同见解。不同乙肝疫苗抗原来源于不同的表达系统 ,糖基化程度和生产工艺有所不同 ,由此引起保护率、抗体水平和免疫持久性的差异如何 ?以及以何种方法评价方能较科学地反映疫苗质量 ,均为乙肝预防工作中亟待解决的重大问题。开展这方面的研究 ,对确定我国乙肝疫苗生产发展的方向 ,即选择、推广何种类型的乙肝疫苗十分重要 ,为制定疫苗更新换代的行政决策提供依据。本文对疫苗免疫效果考核和保护机制…     

Recombinant-yeast-derived hepatitis B vaccine in healthy adults: safety and two-year immunogenicity of early investigative lots of vaccine

We tested the safety and long-term immunogenicity of two of the early investigative lots of a recombinant-yeast-derived hepatitis B vaccine in immunocompetent adults. Three 10-micrograms doses of recombinant hepatitis B vaccine (Merck Sharp & Dohme Research Laboratories, West Point, PA) were administered by deltoid intramuscular injection at time 0, 1, and 6 months to 65 seronegative adult health workers. Following a complete three-injection course, 98% of vaccinees acquired anti-HBs, 97% at levels greater than 10 mlU/ml, and 95% maintained such "protective" antibody levels at 1 year. At 2 years, 93% retained antibody, but only 68% had levels greater than 10 mlU/ml. In those who responded to vaccination by achieving any detectable level of antibody, the peak geometric mean titer of anti-HBs, measured at 9 months, was 741 +/- 6 mlU/ml; the geometric mean titer fell to 348 +/- 6 at 1 year and to 66 +/- 7 at 2 years. Side effects were trivial, and levels of yeast antibody, as measured by radioimmunoassay, were not changed from prevaccine levels. No serious adverse effects were encountered, and neither type B nor non-B hepatitis occurred in any vaccine. These findings demonstrate that the recombinant yeast hepatitis B vaccine is safe and immunogenic but that 10 micrograms of the early investigative lots of the recombinant vaccine is less immunogenic than 20 micrograms of the plasma-derived vaccine. Recipients of early investigative vaccine lots should be considered for booster vaccination with currently available, more immunogenic vaccine lots.     

乙型肝炎疫苗长期免疫效果评价及免疫持久性研究

目的 评价我国新生儿乙型肝炎(乙肝)疫苗免疫后的长期保护效果,为乙肝防控和乙肝疫苗HepB免疫策略提供参考.方法 用横断面调查和分层整群抽样的方法,在乙肝疫苗免疫效果观察监测点收集1987-1996年出生(13～22岁)、全程接种乙肝血源疫苗的人群,以及1997-2008年出生(1 ～ 12岁)、全程接种乙肝重组酵母疫苗人群的血清样本和资料;用微粒子酶免疫法检测HBV感染指标,结合本底资料和乙肝疫苗免疫史进行分析.结果 在河北正定、广西隆安、上海黄浦、青海同德和湖南湘潭5个监测点共收集1～12岁重组酵母疫苗免疫人群样本8133例,13 ～22岁血源疫苗免疫人群样本4848例,5个监测点的HBsAg平均阳性率均显著低于本底值,疫苗总体保护效果分别为86.04％～96.14％;河北正定、青海同德和湖南湘潭的年龄分布差异无统计学意义,广西隆安和上海黄浦的结果显示19～22岁人群HBsAg阳性率偏高;Anti-HBs阳性率随免疫年龄增长而下降,重组疫苗免疫人群从1～2岁组的86.84％下降至11～12岁组的46.40％,17 ～18岁组的Anti-HBs阳性率处于较低水平,而19～22岁组出现升高;几何平均浓度(GMC) ＜10 mIU/ml(Anti-HBs阴性)的比例随着年龄增长逐渐升高,100～999.99 mIU/ml和≥1000 mIU/ml的比例随着年龄的增长呈现下降趋势.结论 血源疫苗免疫后13～ 22年、重组酵母疫苗免疫后1～12年的总体保护效果良好;不必开展加强免疫,建议加强监测18岁以上人群的Anti-HBs水平,对GMC＜10 mIU/ml者开展加强免疫.     

Clinical safety and efficacy of first indigenous recombinant hepatitis B vaccine

A pilot study was conducted to assess the clinical safety and immunogenicity of an indigenously developed recombinant hepatitis B vaccine (Shanvac B) in 18 healthy adults. 20 microg of vaccine was administered at 0, 1 and 2 months. Protective anti HBs titres developed in 22%, 77% and 100% one month after 1st, 2nd and 3rd dose of vaccination, respectively. The geometric mean titre after the 3rd dose was 1015.29 mIu/ml. The vaccine was well tolerated with minor local and systemic side effects in 28% and 22%, respectively. The indigenously developed recombinant hepatitis B vaccine is safe, well tolerated and highly immunogenic.     

Comparison of immunogenicity of hepatitis B vaccine between low and normal birth weight infants.

A comparative study was conducted to evaluate the immunogenicity of hepatitis B vaccine in low and normal birth weight infants. Hepatitis B vaccine (Hevac B Pasteur) was given to 50 low birth weight infants and 50 controls, matched by sex and date of delivery. The vaccine was given at birth, 1, 2 and 12 months of age. HBsAg and anti-HBs were assessed at birth, 4, 9 and 13 months of age by the micro-ELISA technique. Using the geometric mean titre of anti-HBs and the seroconversion rate as indicators, the immunogenicity of hepatitis B vaccine in low birth weight infants was as good as in normal birth weight infants.