Successful postexposure vaccination against hepatitis B in chimpanzees

To study the effect of postexposure vaccination, four chimpanzees were vaccinated with hepatitis B (HB) vaccine 4, 8, 48, and 72 hr, respectively, after intravenous injection of an infectious hepatitis B virus (HBV) inoculum. The second and third vaccine inoculations were given 2 and 6 weeks later, i.e., at considerably shorter intervals than recommended either for ordinary prophylactic vaccination or for postexposure vaccination in combination with hepatitis B immune globulin (HBIG). The chimpanzees were followed for 1 year. None showed HBs-antigenemia, liver enzyme elevation (ALT), or histopathological alterations in liver biopsies. Late appearance of anti-HBc was observed only in the serum of the animal whose series of vaccination started 72 hr after HBV inoculation. An unvaccinated control chimpanzee, which received the HBV inoculum only, developed clinical hepatitis B with ALT-elevations and HBs-antigenemia within 2 months of the experimental HBV inoculation. These results indicate that postexposure vaccination against hepatitis B begun within 48 hr after HBV exposure, with short intervals between the vaccine injections, can protect against hepatitis B infection also when concomitant HBIG-prophylaxis is not given.     

Low-dose (2 micrograms) hepatitis B vaccination in medical students: comparable immunogenicity for intramuscular and intradermal routes

In a randomized controlled trial, 165 healthy medical students were immunized either by the intramuscular route (IM group) or by the intradermal route (ID group) with low-dose (2 micrograms) plasma hepatitis B vaccine (HB-VAX) at months 0, 1, 2, and 6. At month 7, protective immunity (anti-HBs greater than 10 IU/l) was observed in 90% (95% confidence interval [Cl]: 84-97) of group IM and in 94% (95% Cl: 89-99) of group ID; also geometric mean titres (IM: 533 IU/l; ID:541 IU/l) were very similar at month 7. Sixty-six (IM: 29; ID: 37) of 107 vaccinees with anti-HBs less than 1,000 IU/l at month 7 received a 2 micrograms booster injection at month 12. Long-term immunity (anti-HBs greater than 1,000 IU/l) was finally observed in 58% for group IM and 66% for group ID. For low-dose hepatitis B immunization, which reduces costs to about 16%, the IM route is to be preferred in young healthy individuals in view of an ease of administration, avoidance of long-term local side effects, and the known protective immunity of intramuscularly induced anti-HBs antibodies.     

新生儿乙型肝炎疫苗免疫后13年效果观察

目的 研究乙型肝炎的远期免疫效果。方法 采用单纯随机方法连续13年对1986年出生并接种乙型肝炎疫苗的儿童进行隔年随访,采血检测HBsAg、抗-HBs、抗-HBc。结果 13年间HBsAg阳性率在0.46%-0.97%之间,未随免疫时间的延长而上升,乙型肝炎疫苗的远期保护效果为81.67%,与近期免疫效果相当。结论 免疫后13年仍无需加强免疫。     

Seroprevalence of hepatitis B virus infection in children in Taipei, 1989: five years after a mass hepatitis B vaccination program

A nationwide hepatitis B vaccination program was launched in Taiwan in 1984. To study the impact of this ongoing program on hepatitis B virus (HBV) infection, a follow-up seroepidemiologic study was carried out in 1989 in a Taipei district where pre-vaccination seroepidemiology had been studied. HBV markers were studied in 1134 apparently healthy children (619 boys and 515 girls) under 13 years of age between March and July 1989. The prevalence of hepatitis B surface antigen (HBsAg) in children under 5 years of age decreased from 9.3% in 1984 to approximately 2% in 1989. A significant decrease in HBsAg prevalence and hepatitis B core antibody in 5- to 8-year-old children who were not immunized against HBV showed that horizontal infection among the older children had also decreased. Thus, this program not only protected vaccinated subjects; the reduction in numbers of highly infectious young HBV carriers also contributed to a lower prevalence of hepatitis B infection and carrier rates in some older children. This study demonstrates that hepatitis B vaccination is effective in protecting the majority of children in hyperendemic areas from HBV infection and from becoming chronic carriers.     

Anti-phospholipid antibodies following vaccination with recombinant hepatitis B vaccine

This study was undertaken to evaluate the possible role of hepatitis B recombinant vaccine inducing the synthesis of IgG and IgM anti-cardiolipin antibodies (aCL), antibodies against beta(2)GPI (anti-beta(2)GPI), lupus anti-coagulant (LA), anti-nuclear antibodies and antibodies against extractable nuclear antigens (anti-ENA). The study population consisted of 85 healthy students (63 female, 22 male; mean age 20.8 years), vaccinated with three doses of recombinant DNA hepatitis B vaccine. One month after vaccination with the first dose of hepatitis B vaccine a minority of vaccinated individuals showed changes in IgG or IgM aCL or anti-beta(2)GPI or LA activity (P < 0.001). Among subjects in whom changes of IgG anti-beta(2)GPI were observed, a significantly higher number of increased (8/85) than decreased (2/85) values were found (P < 0.01). Analyses of paired data showed that differences in aCL or anti-beta(2)GPI levels before vaccination or 1 month later did not reach statistical significance. In two people aCL transitorily reached medium positivity after the first dose of hepatitis B vaccine with a drop 5 months later. Similar evident anti-beta(2)GPI fluctuation was also observed in one person. Another participant was initially low positive for IgG anti-beta2GPI and the levels were increasing after vaccination. Two participants became positive for anti-nuclear antibodies during 6 months' follow-up. There were no sex-dependent differences in tested antibodies observed and no associations between levels of aPL and levels of anti-HBV antibodies. We conclude that HBV can induce aPL, although rarely. In genetically susceptible individuals or together with some other triggers such combination might confer the risk of developing a continuous autoimmune response in an individual.     

Hepatitis B vaccination in children: The Taiwan experience

The world's first nationwide hepatitis B virus (HBV) universal vaccination program for infants was launched in Taiwan in July, 1984. All infants received three to four doses plasma or recombinant HBV vaccines. In addition, infants of HBeAg-positive mothers received 0.5 ml of hepatitis B immunoglobulin within 24 hours after birth. The vaccination coverage rate is as high as 97%. Seroprevalence of hepatitis B surface antigen (HBsAg) declined from 9.8% (prevaccination period) to 0.6% in children in Taipei City after 20 years of mass vaccination. The seropositive rates for HBsAg, antibody to HBsAg, and antibody to hepatitis B core antigen were 1.2%, 50.5%, and 3.7%, respectively, in those born after the vaccination program (< 20 years old) in 2004. In line with the decrease of chronic HBV infection, the incidence of hepatocellular carcinoma (HCC) also decreased in children in Taiwan. From 1981 to 1994, the incidence of HCC in 6- to 9-year-olds declined from 0.52/100,000 for those born between 1974 and 1984 to 0.13 for those born between 1984 and 1986 (p < 0.001). We extended the observation to 2000, the incidence of HCC per 100,000 children declined from 0.54 to 0.20. The prevalence of a determinant mutants (amino acids 121–149 of HBsAg) in Taiwanese carrier children was 7.8% (eight out of 103) in 1984, increased to 19.6% (10 out of 51) in 1989, peaked at 28.1% (nince out of 32) in 1994, and remained stationary at 23.1% (three out of 13) and about 25% in 1999 and 2004, respectively; it was higher in those fully vaccinated compared with those not vaccinated. The other group of subjects who are susceptible to vaccine failure is the immunocompromized hosts. We observed some de novo HBV infection in children after liver transplantation. Despite of the success of hepatitis B immunization, childhood chronic HBV infection and HCC were not eliminated by the universal vaccination program. Among those HBsAg carriers born after the vaccination program, 89% of their mothers were found to be positive for HBsAg, indicating the importance of maternal transmission. This was also true in the mothers of children with HCC, of them 96% were HBsAg positive. After two decades of universal infant HBV vaccination, we found this program provides long-term protection for up to more than 20 years, and a universal booster is not required for the primary HBV vaccinees before adulthood. Mother-to-child transmission, although largely diminished, is still the main cause for immunoprophylaxis failure. The emergence of escape mutant did not impose increased risk of chronic infection at present. Nevertheless, development of new vaccines may overcome the vaccine failure.     

Impact of the Expanded Program of Immunization against hepatitis B infection in school children in Malaysia

The implementation of the Expanded Program of Immunization (EPI) in 1989 has dramatic impact on hepatitis B virus (HBV) infection in school children in Malaysia. A cross-sectional seroprevalence study of HBV infection in 190,077 school children aged 7–12 years from 1997 to 2003 showed a steady decline of HBV surfacce antigen (HBsAg) prevalence rate from 2.5% for children born in 1985 to 0.4% among school children born in 1996. The overall prevalence of HBsAg was 0.6%, 0.7% in males and 0.6% in females. Over 92.7% of school children had been vaccinated with HBV vaccine, in which 93.7% were vaccinated under the EPI and 6.3% on voluntary basis. The school children vaccinated under EPI had a 0.4% HBsAg carrier rate, which was significantly lower than school children vaccinated on a voluntary basis (HBsAg carrier rate 1.3%) and non-vaccinated school children (HBsAg carrier rate 2.7%), suggesting that HBV vaccination of infants was the most effective measure in preventing vertical transmission of HBV in the hyperendemic region.     

A mathematical model predicting anti-hepatitis B virus surface antigen (HBs) decay after vaccination against hepatitis B

The determination of serum levels of antibodies against hepatitis B virus surface antigen (anti-HBs) after hepatitis B vaccination is currently the only simple test available to predict the decay of protection and to plan the administration of booster doses. A total of 3085 vaccine recipients of plasma-derived and recombinant vaccine have been followed for 10 years to determine the kinetics of anti-HBs production and to construct a mathematical model which could efficiently predict the anti-HBs level decline. The anti-HBs peak level was reached 68 days after the last dose of recombinant vaccine and 138 days after the last dose of plasma-derived vaccines. The age of vaccinees negatively influenced the anti-HBs levels and also the time necessary to reach the anti-HBs peak. A bilogarithmic mathematical model (log10 level, log10 time) of anti-HBs decay has been constructed on a sample of recombinant vaccine recipients and subsequently validated on different samples of recombinant or plasma-derived vaccine recipients. Age, gender, type of vaccine (recombinant or plasma-derived), number of vaccine doses (three or four) did not influence the mathematical model of antibody decay. The program can be downloaded at the site: http:@www2.stat.unibo.it/palareti/vaccine.htm . Introducing an anti-HBs determination obtained after the peak, the program calculates a prediction of individual anti-HBs decline and allows planning of an efficient booster policy.     

Long-term persistence of antibodies induced by vaccination and safety follow-up, with the first combined vaccine against hepatitis A and B in children and adults

It is important to monitor the long-term persistence of antibodies induced by vaccination. Four cohorts were followed for their long-term immunity after vaccination with a combined hepatitis A and B vaccine (Twinrix; SmithKline Beecham Biologicals, Rixsenart, Belgium). Two cohorts of adults (ages 17-60 years), one of 1-6-year-olds, and one of 6-15-year-olds were vaccinated following a 0, 1, and 6-month schedule. Follow-up data until month 72 (adults) and month 60 (children) are available. At month 72, antibody to hepatitis A virus (anti-HAV) seropositivity (S+) was 100% for both adult cohorts (n = 40 and n = 47) and 95% and 89% of the vaccinees were seroprotected against hepatitis B virus (HBV), respectively. The geometric mean titres (GMTs; mIU/ml) for anti-HAV were 977 and 542 and the GMTs for the antibody to hepatitis B surface antigen (anti-HBs) were 322 and 90. For 1-6-year-olds at month 60 (n = 39), anti-HAV S+ was 100% with a GMT of 479 and 97% were protected against HBV with a GMT of 195. At month 60 for the 6-15-year-olds (n = 42), anti-HAV S+ was 100% with a GMT of 990 and 95% were protected against HBV with a GMT of 263. There have been no safety issues during the follow-up. In the past 5 years, a postmarketing surveillance system was available. Using this system, all spontaneous adverse events are collected and archived. Although infrequent, the most commonly reported adverse events after more than 13 million doses were allergic-type reactions followed by fever and injection site reactions. The combined hepatitis A and B vaccine is safe and is well tolerated. Immunity provided by the vaccine remains high in adults and children with comparable results to those obtained with monovalent vaccines.     

The woodchuck: A model for therapeutic vaccination against hepadnaviral infection

Interferon-α and nucleoside analogues are available for the treatment of chronic hepatitis B virus (HBV) infection but do not lead to a satisfactory result. New findings about the immunological control of HBV during acute infection suggest the pivotal role of T-cell mediated immune responses. Several preclinical and clinical trials were undertaken to explore the possibility of stimulating specific immune responses in chronically infected animals and patients by vaccination. However, vaccination with commercially available HBV vaccines in patients and immunization in woodchucks with core or surface proteins of woodchuck hepatitis virus (WHV) did not result in effective control of HBV and WHV infection, suggesting that new formulations of therapeutic vaccines are needed. Some new approaches combining antiviral treatments with nucleoside analogues, DNA vaccines and protein vaccines were tested in the woodchuck model. It could be shown that therapeutic vaccinations are able to stimulate specific B- and T-cell responses and to achieve transient suppression of viral replication. These results suggest the great potential of therapeutic vaccination in combination with antivirals to reach an effective and sustained control of HBV infection.     

Type 1 interferon augments DNA-based vaccination against hepatitis C virus core protein

Eradication of chronic hepatitis C virus (HCV) infection depends upon a broad-based cellular immune response. Genetic immunization stimulates such a response, but the resultant activity is generally weak. Type 1 interferons (IFNs), which are known for their direct anti-viral and anti-proliferative properties, possess vigorous immunomodulatory properties. The aim of this study was to assess the capacity of IFN-alpha to augment the cellular immune response to DNA vaccination against HCV core protein. Three types of IFN-alpha were investigated: the non-species-specific hybrid IFN A/D, human pegylated IFN-alpha, and a plasmid that expressed murine IFN-alpha. Low doses of hIFN-A/D and hPegIFN-alpha augmented three to fourfold the cellular immune response to DNA-based vaccination, determined in conventional CTL assays, as well as in an in vivo tumor challenge model. Importantly, augmentation occurred within a narrow concentration range; a further increase in IFN dosage suppressed the CTL response significantly. Humoral immunity showed a very similar pattern of augmentation. These findings demonstrate that the immunomodulatory properties of IFN-alpha can be exploited to augment DNA based immunization, but it is important to consider the effects of dose on both cellular and humoral immune response for optimal augmentation.     

Evaluation of a reduced dose of hepatitis B vaccine administered intradermally

Intradermal inoculation of hepatitis B vaccine (HBsAg subtype adw) caused no side effects, but the vaccine was less immunogenic than following intramuscular administration. Intradermal inoculation does not, therefore, offer a major advantage to the generally used intramuscular immunization. A single multisite intradermal administration of a reduced dose of vaccine did not result in a more rapid seroconversion compared to intramuscular inoculation. Although the antibody levels were similar after two intradermal or intradermal or intramuscular injections given 1 month apart, the booster (third injection) at 6 months resulted in anti-HBs levels that were about 10 times higher following intramuscular inoculation as compared to intradermal. All persons immunized developed anti-HBs. The levels of anti-HBs (a and w) were about 30-40% of the total anti-HBs, and the proportion did not change significantly during the course of immunization. Cross-protection against all HBV strains is thus also assured after intradermal administration of vaccine containing only one HBsAg subtype (adw). A skin reaction was elicited only in a small proportion of anti-HBs-positive individuals, and the reaction correlated roughly with the immune responses.     

Development of multiple sclerosis after vaccination against hepatitis B: a study based on human leucocyte antigen haplotypes

The aetiology of multiple sclerosis (MS) is still not fully understood. Infectious agents are believed to play a role in the development of this multifactorial disease. Cases in which this disease occurs after administration of both plasma-derived and recombinant hepatitis B vaccines have been reported. In this study, we compared a group of 11 MS patients who developed first clinical symptoms after hepatitis B vaccination (group I) with 71 MS patients who were never vaccinated against hepatitis B and were negative for hepatitis B serology (group II), and 20 healthy controls (group III). Mean age was 27.75 years (19-39) in group I, 30.16 years (18-50) in group II, and 34.4 years (18-50) in group III. Mean attack rate after 2 years was 1.5 in group I and 1.63 in group II. Mean Expanded Disability Status Scale score after 2 years was 1.31 in group I and 1.89 in group II. Human leucocyte antigen (HLA) typing and serology for hepatitis B surface antigen were performed in all groups. In groups I and II, HLA-DR2 was more frequent than in normal healthy subjects. This reflects the general role of HLA in the pathogenesis of MS but suggests that antigen presentation by different HLA is not involved in the development of MS after hepatitis B vaccination. Since there was no difference in the clinical features between vaccinated and nonvaccinated MS patients, this study supports recent reports that hepatitis B vaccination is safe in MS patients and that hepatitis B vaccination is not involved in the development of MS.     

Cortisol and cardiovascular reactions to mental stress and antibody status following hepatitis B vaccination: a preliminary study

This study examined possible neuroendocrine mechanisms underlying the association between stress and antibody response to vaccination. Hepatitis B antibody titers were obtained, and salivary cortisol and cardiovascular activity measured during baseline, mental arithmetic, and recovery in 30 undergraduates. It was hypothesised that higher reactivity would be associated with poorer antibody status. Compared to individuals with high antibody titers, those with low titers had significantly lower cortisol levels throughout, exhibited a significantly attenuated end-of-task reduction in cortisol relative to resting baseline, and had larger cardiac output and inotropic reactions, but smaller increases in total peripheral resistance, to mental arithmetic. In sum, variations in indices of both hypothalamic pituitary adrenocortical axis and sympathetic nervous system activity were associated with individual differences in immune response to vaccination.     

乙肝疫苗母-婴阻断失败者病毒全基因变异分析

Objective To determine the factors responsible for failed postnatal immunoprophylaxis for hepatitis B virus(HBV) in Qidong, China. Methods Eleven children who developed into chronic HBV infection after receiving HBIG and HBV recombinant vaccines were recruited into the study. Eleven paired mothers with chronic hepatitis and other 6 mothers whose children successfully generated anti-HBs after im-munoprophylaxis were included as the control in the study. Full-length HBV DNA was amplified through ser-um sample by PCR method and underwent cloning and sequencing. HBV DNA level was quantified by real-time PCR. Results The mean levels of HBV DNA in mothers who had HBV DNA positive children and healthy children were ( 1.2 ×107± 3.1 × 106 ) copies/ml and ( 1.6× 107±8.8×106 ) copies/ml, respec-tively. There was no significant difference between the groups (P >0.05). Meanwhile, viral load in chil-dren was unrelated to that in their mothers (r2 =0.2429). In 11 HBV DNA positive children, 4(36.4% ) demonstrated amino acid substitutions in HBsAg "a" determinant region with 6 different types, I.e. T125A, I126T, Q129H, M133V, D144V and G145A. All of the mothers showed the wild-type sequence in "a" epitope, indicating surface escape mutants were not acquired from the initial infection, but developed under the immune pressure. The mutation rates after immunoprophylaxis for preS1, preS2, S, X, preC/C and P genes were 0.38%, 0. 22%, 0.27%, 0.17%, 0.11%, and 0.11%, respectively, nt2999-3157 in preS1, nt529-677 in S, nt1955-2016 in C, nt923-1001 and nt2489-2602 in P genes were among the hottest muta-tional spots throughout the HBV genome. Conclusion HBV mutation may occur in all the open readingframes after passive and active immunoprophylaxis. In addition to S gene, HBV preS and P genes could alsoassociate with the escape mutants.     

乙肝疫苗母-婴阻断失败者病毒全基因变异分析

Objective To determine the factors responsible for failed postnatal immunoprophylaxis for hepatitis B virus(HBV) in Qidong, China. Methods Eleven children who developed into chronic HBV infection after receiving HBIG and HBV recombinant vaccines were recruited into the study. Eleven paired mothers with chronic hepatitis and other 6 mothers whose children successfully generated anti-HBs after im-munoprophylaxis were included as the control in the study. Full-length HBV DNA was amplified through ser-um sample by PCR method and underwent cloning and sequencing. HBV DNA level was quantified by real-time PCR. Results The mean levels of HBV DNA in mothers who had HBV DNA positive children and healthy children were ( 1.2 ×107± 3.1 × 106 ) copies/ml and ( 1.6× 107±8.8×106 ) copies/ml, respec-tively. There was no significant difference between the groups (P >0.05). Meanwhile, viral load in chil-dren was unrelated to that in their mothers (r2 =0.2429). In 11 HBV DNA positive children, 4(36.4% ) demonstrated amino acid substitutions in HBsAg "a" determinant region with 6 different types, I.e. T125A, I126T, Q129H, M133V, D144V and G145A. All of the mothers showed the wild-type sequence in "a" epitope, indicating surface escape mutants were not acquired from the initial infection, but developed under the immune pressure. The mutation rates after immunoprophylaxis for preS1, preS2, S, X, preC/C and P genes were 0.38%, 0. 22%, 0.27%, 0.17%, 0.11%, and 0.11%, respectively, nt2999-3157 in preS1, nt529-677 in S, nt1955-2016 in C, nt923-1001 and nt2489-2602 in P genes were among the hottest muta-tional spots throughout the HBV genome. Conclusion HBV mutation may occur in all the open readingframes after passive and active immunoprophylaxis. In addition to S gene, HBV preS and P genes could alsoassociate with the escape mutants.     

乙肝疫苗母-婴阻断失败者病毒全基因变异分析

Objective To determine the factors responsible for failed postnatal immunoprophylaxis for hepatitis B virus(HBV) in Qidong, China. Methods Eleven children who developed into chronic HBV infection after receiving HBIG and HBV recombinant vaccines were recruited into the study. Eleven paired mothers with chronic hepatitis and other 6 mothers whose children successfully generated anti-HBs after im-munoprophylaxis were included as the control in the study. Full-length HBV DNA was amplified through ser-um sample by PCR method and underwent cloning and sequencing. HBV DNA level was quantified by real-time PCR. Results The mean levels of HBV DNA in mothers who had HBV DNA positive children and healthy children were ( 1.2 ×107± 3.1 × 106 ) copies/ml and ( 1.6× 107±8.8×106 ) copies/ml, respec-tively. There was no significant difference between the groups (P >0.05). Meanwhile, viral load in chil-dren was unrelated to that in their mothers (r2 =0.2429). In 11 HBV DNA positive children, 4(36.4% ) demonstrated amino acid substitutions in HBsAg "a" determinant region with 6 different types, I.e. T125A, I126T, Q129H, M133V, D144V and G145A. All of the mothers showed the wild-type sequence in "a" epitope, indicating surface escape mutants were not acquired from the initial infection, but developed under the immune pressure. The mutation rates after immunoprophylaxis for preS1, preS2, S, X, preC/C and P genes were 0.38%, 0. 22%, 0.27%, 0.17%, 0.11%, and 0.11%, respectively, nt2999-3157 in preS1, nt529-677 in S, nt1955-2016 in C, nt923-1001 and nt2489-2602 in P genes were among the hottest muta-tional spots throughout the HBV genome. Conclusion HBV mutation may occur in all the open readingframes after passive and active immunoprophylaxis. In addition to S gene, HBV preS and P genes could alsoassociate with the escape mutants.     

乙肝疫苗母-婴阻断失败者病毒全基因变异分析

Objective To determine the factors responsible for failed postnatal immunoprophylaxis for hepatitis B virus(HBV) in Qidong, China. Methods Eleven children who developed into chronic HBV infection after receiving HBIG and HBV recombinant vaccines were recruited into the study. Eleven paired mothers with chronic hepatitis and other 6 mothers whose children successfully generated anti-HBs after im-munoprophylaxis were included as the control in the study. Full-length HBV DNA was amplified through ser-um sample by PCR method and underwent cloning and sequencing. HBV DNA level was quantified by real-time PCR. Results The mean levels of HBV DNA in mothers who had HBV DNA positive children and healthy children were ( 1.2 ×107± 3.1 × 106 ) copies/ml and ( 1.6× 107±8.8×106 ) copies/ml, respec-tively. There was no significant difference between the groups (P >0.05). Meanwhile, viral load in chil-dren was unrelated to that in their mothers (r2 =0.2429). In 11 HBV DNA positive children, 4(36.4% ) demonstrated amino acid substitutions in HBsAg "a" determinant region with 6 different types, I.e. T125A, I126T, Q129H, M133V, D144V and G145A. All of the mothers showed the wild-type sequence in "a" epitope, indicating surface escape mutants were not acquired from the initial infection, but developed under the immune pressure. The mutation rates after immunoprophylaxis for preS1, preS2, S, X, preC/C and P genes were 0.38%, 0. 22%, 0.27%, 0.17%, 0.11%, and 0.11%, respectively, nt2999-3157 in preS1, nt529-677 in S, nt1955-2016 in C, nt923-1001 and nt2489-2602 in P genes were among the hottest muta-tional spots throughout the HBV genome. Conclusion HBV mutation may occur in all the open readingframes after passive and active immunoprophylaxis. In addition to S gene, HBV preS and P genes could alsoassociate with the escape mutants.