Long-term persistence of anti-HBs after vaccination against HBV: an 18 year experience in health care workers

Hepatitis B vaccination at three months of age: a successful strategy?

Vaccination of infants, children and adolescents against the hepatitis B virus (HBV) is mandatory in Italy. It is crucial to assess whether vaccinated subjects have protective antibody level during adulthood when the risk of HBV infection increases due to lifestyle or occupational exposure. Two groups of students attending to University of Padova Medical School were enrolled between 2004 and 2011 and HBV antibodies and antigens were measured. The first group (Group A) comprised students vaccinated at three months of age and the second group (Group B) comprised students vaccinated after the first year of life. The follow-up was 18.0 (Group A) and 17.9 (Group B) years. The students vaccinated at three months of age had a higher rate of non-protective antibodies (47.2%) comparing to those vaccinated after the first year of life (17.0%, P<0.0001) with a significantly lower antibody level (P<0.001). The rate of non-protective antibodies was inversely related to vaccination age. The results clearly show that children vaccinated after the first year of life are better protected against HBV. On the other hand, both groups show a good immunological memory as evidenced by the achievement of protective antibody level after the booster dose in 97.8% of subjects.

DTaP-IPV-Hep B-Hib vaccine (Hexaxim®) : a review of its use in primary and booster vaccination

Hexaxim(®) (DTaP-IPV-Hep B-Hib) is a new, thiomersal-free, fully liquid, hexavalent combination pediatric vaccine containing diphtheria and tetanus toxoids, acellular pertussis, inactivated poliovirus, recombinant hepatitis B virus surface antigen produced in the yeast Hansenula polymorpha, and Haemophilus influenzae type b polysaccharide (polyribosylribitol phosphate) conjugated to tetanus toxoid. It is currently registered in markets outside of the EU for primary vaccination of infants from 6 weeks of age and for booster vaccination up to 24 months of age. In randomized controlled trials, primary vaccination of infants with Hexaxim(®) using various immunization schedules was highly immunogenic for all vaccine component antigens regardless of the administration schedule, producing high levels of seroprotection or seroconversion for each antigen. Hexaxim(®) was as immunogenic as the comparator DTwP- or DTaP-based vaccines in these studies. The serological responses were generally sustained at high levels over a follow-up of ≈1 year, and booster vaccination at 15-18 months further enhanced the immune response. Hexaxim(®) was less reactogenic than a DTwP-based combination vaccine, and displayed a tolerability profile similar to those of the comparator DTaP-based combination vaccines. Thus, Hexaxim(®) provides effective seroprotection or seroconversion against six major childhood diseases simultaneously, both as primary and booster vaccination, and offers the benefits and convenience of a fully liquid, ready-to-use vaccine.

Long-term response rates of successful hepatitis B vaccination in HIV-infected patients

BACKGROUND

Data on long-term response rates after successful primary hepatitis B (HBV) vaccination in HIV-infected patients are scarce.

OBJECTIVE

To evaluate the durability of an effective anti-HBs titer up to 5 years after primary vaccination in a cohort of 155 HIV-infected adults.

METHODS

From a previous multicenter HBV vaccination trial we selected patients with an anti-HBs titer of ≥10 IU/l 28 weeks after the first vaccination. The anti-HBs titer was measured in annually stored plasma samples up to 5 years after vaccination. Patients with decreasing anti-HBs titers <10 IU/I were defined as transient responders (TR) and with persistent anti-HBs titers ≥10 IU/I as long-term responders (LTR^).

RESULTS

We included 155 patients, 87 were TR and 68 LTR. Mean age, percentage of female participants and duration of HAART use at primary vaccination were similar in LTR and TR. Anti-HBs level after primary vaccination was the strongest predictor for the durability of anti-HBs. Anti-HBs >100-1000 IU/I and >1000 resulted in an OR 8.3, 95% CI 3.38-20.16; p<0.0001 and OR 75.6, 95% CI 13.41-426.45; p<0.0001 versus anti-HBs titer of 10-100 IU/I after primary vaccination respectively. The mean time to loss of an effective anti-HBs titer was 2.0, 3.7 and 4.4 years respectively, for patients with an anti-HBs titer of 10-100 IU/I, >100-1000 IU/I and >1000 IU/I at primary vaccination. An undetectable HIV-RNA load and use of HAART during vaccination and at follow-up were, though not significantly, associated a higher long-term persistence of an effective antibody titer.

CONCLUSION

The durability of an effective anti-HBs level appears to be significantly related to the height of the antibody titers after the primary immunization procedure. Schedules to improve the vaccination response in HIV-infected patients therefore seem to be justified. Whether a HBV booster is indicated remains to be elucidated.

Associated factors for recommending HBV vaccination to children among Georgian health care workers

Background

Most cases of hepatitis B virus (HBV) infection and subsequent liver diseases can be prevented with universal newborn HBV vaccination. The attitudes of health care workers about HBV vaccination and their willingness to recommend vaccine have been shown to impact HBV vaccination coverage and the prevention of vertical transmission of HBV. The purpose of this study was to ascertain the factors associated with health care worker recommendations regarding newborn HBV vaccination.

Methods

A cross-sectional study of prevalence and awareness of hepatitis B and hepatitis B vaccine was conducted among randomly selected physicians and nurses employed in seven hospitals in Georgia in 2006 and 2007. Self-administered questionnaires included a module on recommendations for HBV, HCV and HIV.

Results

Of the 1328 participants included in this analysis, 36% reported recommending against hepatitis B vaccination for children, including 33% of paediatricians. Among the 70.6% who provided a reason for not recommending HBV vaccine, the most common concern was an adverse vaccine event. Unvaccinated physicians and nurses were more likely to recommend against HBV vaccine (40.4% vs 11.4%, PR 3.54; 95% CI: 2.38, 5.29). Additionally, health care worker age was inversely correlated with recommendations for HBV vaccine with older workers less likely to recommend it.

Conclusion

Vaccinating health care workers against HBV may provide a dual benefit by boosting occupational safety as well as strengthening universal coverage programs for newborns.

Hepatitis B revaccination for healthcare workers who are anti-HBs-negative after receiving a primary vaccination series

INTRODUCTION

This study aimed to evaluate the response to hepatitis B (HB) revaccination of healthcare workers (HCW) who are negative for antibodies to HB surface antigen (anti-HBs) after a complete vaccination series.

METHODS

HCW whose anti-HBs test was performed > 90 days after a HB vaccination course were given a 4th dose. A post-vaccination test was done within 30 to 90 days.

RESULTS

One hundred and seventy HCW were enrolled: 126 (74.1%) were anti-HBs-positive after the 4th dose.

CONCLUSIONS

Rechecking anti-HBs after the 4th HB vaccine dose is a practical approach in case of post-vaccination tests performed >90 days after the full vaccination course.

Long-term persistence of seroprotection by hepatitis B vaccination in healthcare workers of southern Italy

BACKGROUND

The impact of hepatitis B virus (HBV) vaccination campaigns on HBV epidemiology needs to be evaluated, in order to assess the long-term immunity offered by vaccines against HBV.

OBJECTIVES

To evaluate the current status of anti-HBV vaccine coverage among healthcare workers (HCWs) in Southern Italy, and to determine the long-term persistence of antibodies to hepatitis B surface antigens (anti-HBs) in such a cohort of subjects.

PATIENTS AND METHODS

A longitudinal, retrospective seroepidemiological survey was conducted among 451 HCWs, who were working at or visiting, the Occupational Health Department of a city hospital, in Catania, Italy, between January 1976 and December 2010.

RESULTS

At the 30-year follow-up (mean follow-up 10.15 ± 5.96 years, range 0.74-30), 261 HCWs had detectable anti-HBs titers indicating a persistence of seroprotection of 89.4% (out of 292 anti-HBs positive results, three months after vaccination). An inadequate vaccination schedule was the strongest predictor of antibody loss during follow-up (OR = 8.37 95% CI: 5.41-12.95, P < 0.001). A Kaplan-Maier survival curve revealed that the persistence of anti-HBs 30 years after vaccination, was 92.2% for high responders, while it was only 27.3% for low responders (P = 0.001).

CONCLUSIONS

A good level of seroprotection persisted in 57.9% of the subjects after 30 years. Factors related to this immunization status confirmed the importance of vaccinating HCWs early in their careers and ensuring an adequate vaccination schedule. However, with particular reference to the low rate of hepatitis B vaccine coverage among HCWs in Southern Italy, the implementation of a new educational intervention as part of an active vaccination program is needed.

Vaccination against hepatitis B with 4-double doses increases response rates and antibodies titers in HIV-infected adults

BACKGROUND

Antibody responses to standard regimens of hepatitis B (HBV) vaccination are lower in HIV-infected subjects and the best hepatitis B vaccine schedule in this population is not known.

OBJECTIVE

To assess the immunogenicity and to evaluate predictors of serologic response of a modified regimen of a HBV recombinant vaccine in a cohort of HIV-infected subjects.

METHODS

HIV-infected subjects received 4 doses (40 μg) of a recombinant HBV vaccine at 0, 1, 2 and 6 months. Demographic information as well as CD4 cell count and plasma viral load were assessed at baseline. Protective and strong responses were defined as an anti-HBs titer ≥10 mIU/mL and ≥100 mIU/mL, respectively and were evaluated one month after the third and the fourth doses.

RESULTS

163 HIV-infected individuals were evaluated 67 (40%) were male and median age was 37 years. Median CD4 cell count was 385 cells/mm(3) and 113 (70%) had undetectable HIV-1 viral load. Protective antibody response was observed in 83 and 91% and a strong antibody response was observed in 62 and 80% of the subjects after 3 and 4 doses, respectively. In a multivariate logistic model undetectable HIV-1 viral load and higher CD4 cell counts were independent predictors of a strong antibody response after 4 doses. Patients with undetectable HIV viral load were almost 3 times more likely to have anti-HBs titers above 100 mIU/mL than those with detectable viral load.

CONCLUSIONS

A 4-double-dose regimen of a recombinant HBV vaccine increased response rates and determined higher antibody titers which may translate in prolonged protection against HBV. Inclusion of a fourth dose of HBV vaccine for HIV-infected subjects should be considered in the public health setting.

Hepatitis B surface antigen-1018 ISS adjuvant-containing vaccine: a review of HEPLISAV™ safety and efficacy

Immunization represents the most effective approach to the prevention of hepatitis B virus infection and the long-term complications of chronic disease, including liver cancer and liver failure. Current vaccines require three doses to achieve maximal immunogenicity and fail to produce long-lasting protection in 5-10% of immune-competent individuals and in a much larger proportion of immune-compromised patients. Immunostimulatory DNA sequence (ISS) vaccine adjuvants, when combined with vaccine antigens, may increase immunogenicity and reduce the number of required doses to achieve this goal. 1018 ISS plus recombinant hepatitis B surface antigen has been demonstrated to achieve these goals in immune competent and vaccine-hyporesponsive populations without compromising recipient safety.

Five years follow-up following two or three doses of a hepatitis B vaccine in adolescents aged 11-15 years: a randomised controlled study

BACKGROUND

The standard three-dose schedule of hepatitis B vaccines is frequently not completed, especially in adolescents. A primary study has confirmed the equivalence of a two-dose schedule of an Adult formulation of hepatitis B vaccine [Group HBV_2D] to a three-dose schedule of a Paediatric formulation in adolescents (11-15 years) [Group HBV_3D]. This follow-up study evaluated the five year persistence of antibody response and immune memory against the hepatitis B surface (anti-HBs) antigens five years after completion of primary vaccination.

METHODS

A total of 234 subjects returned at the Year 5 time point, of which 144 subjects received a challenge dose of hepatitis B vaccine. Blood samples were collected yearly and pre- and post-challenge dose to assess anti-HBs antibody concentrations.

RESULTS

At the end of five years, 79.5% (95% confidence interval [CI]: 71.7 - 86.1) and 91.4% (95% CI: 82.3 - 96.8) of subjects who received the two-dose and three-dose schedules, respectively had anti-HBs antibody concentrations ≥ 10 mIU/mL. Post-challenge dose, all subjects had anti-HBs antibody concentration ≥ 10 mIU/mL and >94% subjects had anti-HBs antibody concentration ≥ 100 mIU/mL. All subjects mounted a rapid anamnestic response to the challenge dose. Overall, the challenge dose was well-tolerated.

CONCLUSION

The two-dose schedule of hepatitis B vaccine confers long-term immunogenicity and shows evidence of immune memory for at least five years following vaccination.

TRIAL REGISTRATION

Clinical Trials NCT00343915, NCT00524576.

Booster dose vaccination for preventing hepatitis B

BACKGROUND

Antibodies against hepatitis B surface antigen (HBs) wane over time after vaccination for hepatitis B (HB); hence, the duration of protection provided by the vaccine is still unknown but may be evaluated indirectly by measuring the anamnestic immune response to booster doses of vaccine.

OBJECTIVES

To assess the benefits and harms of booster dose hepatitis B vaccination for preventing HB infection.

SEARCH STRATEGY

We searched The Cochrane Hepato-biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 4, 2010) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, conference databases, and reference lists of articles to May 2010. We also contacted authors of articles and manufacturers.

SELECTION CRITERIA

Randomised clinical trials addressing anamnestic immune response to booster of HB vaccine five years or more after primary vaccination in apparently healthy participants, vaccinated in a 3-dose or 4-dose schedules of HB vaccine without receiving additional dose or immunoglobulin.

DATA COLLECTION AND ANALYSIS

Two authors made the decisions if the identified publications on studies met the inclusion criteria or not. Primary outcome measures included the proportion with anamnestic immune response in non-protected participants and signs of hepatitis B virus infection. Secondary outcomes were the proportion with local and systemic adverse event events developed following booster dose injection. Weighted proportion were planned to be reported with 95% confidence intervals.

MAIN RESULTS

There were no eligible randomised clinical trials fulfilling the inclusion criteria of this review.

AUTHORS' CONCLUSIONS

We were unable to identify randomised clinical trials on the topic. We need randomised clinical trials to formulate future booster policies for preventing hepatitis B infection.

Determination of immune memory to hepatitis B vaccination through early booster response in college students

The long-term protection of hepatitis B (HB) vaccination has been debated for years. The purpose here was to evaluate the kinetic changes of antibody to HB surface antigen (anti-HBs) and define immune memory of the HB vaccine among college students who had previously received full neonatal immunization against HB. In all, 127 college students aged 18-23 years born after July 1984 who had completed HB vaccination and were seronegative for all three HB viral markers, including HB surface antigen (HBsAg), antibody to HB core protein (anti-HBc), and anti-HBs, were recruited. They received three doses of HB vaccine at enrollment, 1 month and 6 months after enrollment. Their anti-HBs titers were assayed at enrollment, 7-10 days, 1 month, 6 months, and 7 months following the first dose of HB vaccine. The anti-HBs seroprotective rates for subjects 7-10 days, 1 month, 6 months, and 7 months postvaccination were 20.5%, 75.6%, 94.5%, and 99.2%, respectively. Those who were seroprotective at 7 to 10 days after one dose of HB vaccine booster developed significantly higher levels of anti-HBs at 1 and 6 months than those not developing seroprotective anti-HBs response at an earlier timepoint.

CONCLUSION

At least one-quarter of HB vaccinees have lost their immune memory to the HB vaccine when entering college. Immune memory to HB vaccine was identified by early seroconversion, which was present in only 20% of vaccinees in the present study. To ensure higher than 90% anti-HBs seroconversion rates, at least 2 doses of HB booster vaccines are recommended for at-risk youths who received complete HB vaccinations in neonatal or infant periods but are seronegative for HBsAg, anti-HBs, and anti-HBc in adolescence.

Low hepatitis B immunogenicity of a hexavalent vaccine widely used in Germany: results of the German Health Survey for Children and Adolescents, 2003–2006

The success of childhood vaccination against hepatitis B relies on persistence of immunity into adolescence and adulthood. In 2000, two hexavalent vaccines with a hepatitis B component (Hexavac®, Infanrix hexa®) were introduced in Germany. Hexavac was withdrawn in 2005 amidst concerns about its long-term hepatitis B protection. We compared hepatitis B surface antibody (anti-HBs) levels in children fully vaccinated with Hexavac or Infanrix hexa (n=477) in a secondary data analysis of a large cross-sectional health survey in Germany. On average 2·4 years after vaccination, 25·3% of Hexavac vaccinees had anti-HBs levels <10 mIU/ml (95% CI 19·0–32·8) compared to 4·7% of Infanrix hexa vaccinees (95% CI 2·4–8·9). These findings suggest that short-term hepatitis B immunogenicity in Hexavac vaccinees may also be weaker. Further studies are warranted to assess whether Hexavac vaccinees should be re-vaccinated or receive a booster vaccination before these birth cohorts reach adolescence.

Effect of GM-CSF in combination with hepatitis B vaccine on revacination of healthy adult non-responders

OBJECTIVE

To assess the immune effects and safety of using GM-CSF with the yeast-recombinant hepatitis B virus (HBV) vaccine for the re-vaccination of healthy adults who did not respond to a previous vaccination.

METHODS

Study participants included 1784 healthy adults and 100 individuals diagnosed as non-responders. These healthy non-responders were randomly assigned to one of the three treatment groups: Group A (34 individuals) was given 150 microg of granulocyte-macrophage colony stimulating factor (GM-CSF) the first day, then 20 microg of the vaccine; Group B (33 individuals) was given 40 microg of the vaccine only; and, group C (33 individuals) was injected with 20 microg of vaccine each time. All participants were injected three times, at time of study enrollment and one and six months later. Anti-HB surface antigen (HBs) antibody titers were tested before treatment and at one (T1), two (T2) and eight (T8) months post-first injection.

RESULTS

At T1, the rate of anti-HBs antibody(+) in groups A, B and C was 26.47%, 48.48% and 18.18%, respectively (p = .027). At T8, the seropositive rate of group A (64.71%) and group B (75.76%) was significantly higher than in group C (39.39%) (p = .011); the geometric mean of the antibody titer for groups A and B was higher than for group C (p = .0173). All three treatments were safe and well-tolerated.

CONCLUSIONS

Augmentation of the vaccine dose and co-administration of GM-CSF and the standard vaccine dose are effective for HBV vaccine non-responders. In fact, changing the vaccine dose had a better seropositive response than injecting the vaccine in combination with GM-CSF.

Long-term immunogenicity of preservative-free hepatitis B vaccine formulations in adults

Vaccination with recombinant hepatitis B vaccines is highly effective in preventing hepatitis B infection. Recently, a preservative-free (PF) formulation of hepatitis B vaccine [GlaxoSmithKline (GSK) Biologicals, Rixensart, Belgium] has been licensed. The immunogenicity of the PF hepatitis B vaccine and antibody persistence 6 years later was assessed in this study. This formulation was compared with the preservative- containing (PC) formulation of the vaccine and a low-preservative (LP) content formulation. Five hundred forty-one healthy adult subjects were evaluated in the primary study. Over 94% of the subjects in the three study groups had seroprotective anti-HBs antibody concentrations (>or=10 mIU/ml) 1 month after completing primary vaccination. Antibody measurements in 242 healthy adults who returned for the follow-up study and who had received primary vaccination 6 years earlier showed that over 81% of subjects in the three study groups still had anti-HBs antibody concentrations >or=10 mIU/ml. No apparent differences in antibody decline or distribution between the study groups were observed. These results indicate that the removal of preservatives from the hepatitis B vaccine does not affect adversely its immunogenicity both in the short and in the longer term.

Production of surface plasmon resonance based assay kit for hepatitis diagnosis

Hepatitis B surface antibody (HBsAb) imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-L-tyrosine methyl ester) (PHEMAT) film on the surface plasmon resonance (SPR) sensor chip was prepared for diagnosis of HBsAb in human serum. Gold SPR chip surface was modified with allyl mercaptane and, then, HBsAb-imprinted PHEMAT film was formed on the chip surface. Surface characterization of the non-modified, allyl mercaptane modified and HBsAb-imprinted PHEMAT SPR chips were investigated with contact angle, atomic force microscopy (AFM). Kinetic studies were performed using HBsAb positive human serum. In order to determine the kinetic and binding constants, Scatchard, Langmuir, Freundlich and Langmuir-Freundlich models were applied to experimental data. Scatchard curve shows that HBsAb imprinted SPR chip has some surface heterogeneity, SPR chip obeyed the Langmuir adsorption model. The maximum detection limit was 208.2 mIU/mL. K(A) and K(D) values are 0.015 mIU/mL and 66.0 mL/mIU, respectively. Control experiments of the SPR chip were performed using non-immunized, HBsAb negative serum. The control experiment results show that SPR chip does not give any noticeable response to HBsAb negative serum.

Antibody to Hepatitis B Surface Antigen in Vaccinated Health Care Workers

BACKGROUND

Health care workers (HCWs) in Armed Forces are immunised against Hepatitis B virus (HBV), however they are not subjected to anti-HBs (antibody to Hepatitis B surface antigen) assessment after primary vaccination. The present study was undertaken to determine the protection offered by HBV vaccine in HCW.

METHODS

Cross-sectional study was carried out at tertiary care hospital. A total 146 HBV vaccine compliant HCW were evaluated for quantitative anti-HBs by enzyme immune assay.

RESULT

129 (88.4%) subjects had protective levels of anti-HBs. Higher age at vaccination was an important risk factor in low vaccine response. Decline in anti-HBs with time was evident. Anti-HBs levels were more than 10mIU/ml in subjects even after 11 years of primary vaccination. There was no difference in protection in booster and non booster groups.

CONCLUSION

Age is the most important factor in HBV vaccine response. Booster dose of HBV vaccine is not necessary in healthy HCW for atleast ten years after primary vaccination. The study recommends early primary vaccination of HCW and 'initial' anti-HBs assay for confirmation of vaccine response.

Long-term protection of hepatitis B vaccine 18 years after vaccination

INTRODUCTION

This is the third evaluation study of the hepatitis B virus (HBV) vaccination program, initiated in 1989 in Saudi Arabia.

AIMS

This study sought to assess the efficacy and long-term protection of the hepatitis B vaccine among Saudi adolescents.

METHODS

School students between the ages of 16 and 18 years were randomly chosen from high endemic (Aseer), intermediate endemic (Madinah), and low endemic (Al-Qaseem) areas of the country. Hepatitis B surface antigen (HBsAg), hepatitis B core IgG antibody (anti-HBc), and hepatitis B surface antibody (anti-HBs) were measured using standard techniques.

RESULTS

A total of 1355 students (689 males and 666 females) were selected randomly from the three areas. No cases of positive HBsAg or anti-HBc were detected among the study population. Five hundred and ten students (38%) showed protective anti-HBs titers (>/= 10mIU/ml), while 528 (39%) students had undetectable anti-HBs titers (<1 mIU/ml).

CONCLUSIONS

This study shows the excellent efficacy of the HBV vaccination program in Saudi Arabia 18 years after its launch. Based on this study and others, a booster dose for the adult population appears to be unnecessary.

Pre-clinical evaluation of a novel nanoemulsion-based hepatitis B mucosal vaccine

BACKGROUND

Hepatitis B virus infection remains an important global health concern despite the availability of safe and effective prophylactic vaccines. Limitations to these vaccines include requirement for refrigeration and three immunizations thereby restricting use in the developing world. A new nasal hepatitis B vaccine composed of recombinant hepatitis B surface antigen (HBsAg) in a novel nanoemulsion (NE) adjuvant (HBsAg-NE) could be effective with fewer administrations.

METHODOLOGY AND PRINCIPAL FINDINGS

Physical characterization indicated that HBsAg-NE consists of uniform lipid droplets (349+/-17 nm) associated with HBsAg through electrostatic and hydrophobic interactions. Immunogenicity of HBsAg-NE vaccine was evaluated in mice, rats and guinea pigs. Animals immunized intranasally developed robust and sustained systemic IgG, mucosal IgA and strong antigen-specific cellular immune responses. Serum IgG reached > or = 10(6) titers and was comparable to intramuscular vaccination with alum-adjuvanted vaccine (HBsAg-Alu). Normalization showed that HBsAg-NE vaccination correlates with a protective immunity equivalent or greater than 1000 IU/ml. Th1 polarized immune response was indicated by IFN-gamma and TNF-alpha cytokine production and elevated levels of IgG(2) subclass of HBsAg-specific antibodies. The vaccine retains full immunogenicity for a year at 4 degrees C, 6 months at 25 degrees C and 6 weeks at 40 degrees C. Comprehensive pre-clinical toxicology evaluation demonstrated that HBsAg-NE vaccine is safe and well tolerated in multiple animal models.

CONCLUSIONS

Our results suggest that needle-free nasal immunization with HBsAg-NE could be a safe and effective hepatitis B vaccine, or provide an alternative booster administration for the parenteral hepatitis B vaccines. This vaccine induces a Th1 associated cellular immunity and also may provide therapeutic benefit to patients with chronic hepatitis B infection who lack cellular immune responses to adequately control viral replication. Long-term stability of this vaccine formulation at elevated temperatures suggests a direct advantage in the field, since potential excursions from cold chain maintenance could be tolerated without a loss in therapeutic efficacy.

A cohort study to evaluate persistence of hepatitis B immunogenicity after administration of hexavalent vaccines

BACKGROUND

In 2001, two hexavalent vaccines were licensed in Italy (Hexavac, Infanrix Hexa), and since 2002 were extensively used for primary immunization in the first year of life (at 3, 5, 11/12 months of age). In 2005, the market authorization of Hexavac was precautionary suspended by EMEA, because of doubts on long-term protection against hepatitis B virus. The objectives of this study were to evaluate the persistence of antibodies to anti-HBs, in children in the third year of life, and to investigate the response to a booster dose of hepatitis B vaccine.

METHODS

Participant children were enrolled concomitantly with the offering of anti-polio booster dose, in the third year of life. Anti-HBs titers were determined on capillary blood samples. A booster dose of hepatitis B vaccine was administered to children with anti-HBs titers < 10 mIU/ml, with the monovalent precursor product of the previously received hexavalent vaccine. HBsAb titers were tested again one month after the booster.

RESULTS

Sera from 113 children previously vaccinated with Hexavac, and from 124 vaccinated with Infanrix Hexa were tested for anti-HBs. Titers were > or = 10 mIU/ml in 69% and 96% (p < 0,0001) respectively. The proportion of children with titers > or = 100 mIU/ml did also significantly differ among groups (27% and 78%; p < 0,0001).Post-booster, 93% of children achieved titers > or = 10 mIU/ml, with no significant difference by vaccine group.

DISCUSSION

Fifteen months after third dose administration, a significant difference in anti-HBs titers was noted in the two vaccine groups considered. Monovalent hepatitis B vaccine administration in 3-year old children induced a proper booster response, confirming that immunologic memory persists in children with anti-HBs titers < 10 mIU/ml. However, long-term persistence of HBV protection after hexavalent vaccines administration should be further evaluated over time.

Long-term efficacy of hepatitis B vaccination in healthcare workers of Oil Company Hospital, Tehran, Iran (1989-2005)

OBJECTIVE

This study was conducted to evaluate the 16-year efficacy of hepatitis B virus (HBV) vaccine in healthcare workers of Oil Company Hospital, Tehran, Iran.

METHODS

Two hundred healthcare workers were enrolled in the study in 1989. All HBV markers were tested and those with positive HBV markers, positive antihepatitis C virus or anti-HIV were excluded from the study. The remaining participants received three doses of HBV vaccine and again all of our participants were reevaluated in 2005. Hepatitis B surface antigen (HBsAg), antihepatitis B surface antibody (anti-HBsAb), and antihepatitis B core antibody (anti-HBcAb) were checked in all participants and those with anti-HBcAb above 10 IU/l were excluded from the final evaluation.

RESULTS

No participant was positive for HBsAg in either 1989 or 2005. Protective levels of anti-HBsAb were absent in all participants in 1989, but present in 67 (80.7%) participants in 2005 (P<0.001). Anti-HBsAb titer after vaccination was significantly higher in female participants than in male participants (P=0.01). Mean anti-HBsAb titer was 640+/-411.7 IU/l (range: 2-1000 IU/l) and the lowest protective titer was 12 IU/l.

CONCLUSION

According to our results, 80.7% of our participants had a protective titer of anti-HBsAb 16 years after vaccination. Although all anti-HBc positive participants were free of clinical hepatitis and were negative for HBsAg, hepatitis B vaccination was proved to be highly effective in preventing clinically significant infection and chronic carrier status up to 16 years after the primary vaccination. Hence, HBV revaccination may not be mandatory in healthcare workers, according to their sufficient long-term level of anti-HBsAb.

Waning-off effect of serum hepatitis B surface antibody amongst Taiwanese university students: 18 years post-implementation of Taiwan's national hepatitis B vaccination programme

Hepatitis B virus (HBV) infection and its sequelae remain a major health problem for Taiwan. The national hepatitis B (HB) vaccination programme was first launched in 1984 to combat the spread of this infection. This study examined the status of HBV infection amongst students at a Taiwanese university in 2005, 18 years after the implementation of a nation-wide mass HB vaccination programme. In 2005, 5875 new university entrants, who were born during the period 1 July 1976 to 30 June 1988, were subdivided into one of 12 one-year-interval birth-year cohorts. Each student was individually tested for serum hepatitis B surface antigen (HBsAg), Antibody to hepatitis B surface antigen (anti-HBs) and antibody to hepatitis B core antigen (anti-HBc) status. We observed a declining trend of past exposure to HB infection from 48.7% (1976 birth-year cohort) to 5.2% (1987 birth-year cohort). The prevalence of chronic HB infection also declined from 14.5% (1976 birth-year cohort) to 1.9% (1987 birth-year cohort). The prevalence of persistent HB immunity through (earlier) active vaccination declined from 72% (1984 birth-year cohort) to 41.6% (1987 birth-year cohort). The prevalence of HB infection-naïve individuals increased from 18.2% (1984 birth-year cohort) to 53.1% (1987 birth-year cohort). This study demonstrates that as the implementation of the mass HB vaccination programme in 1984, the incidence of HB infection in Taiwan has declined, although a 'waning-off' effect of serum anti-HBs to low or undetectable levels, which may not provide protection, amongst this student population has arisen, 18 years following the implementation of the nation-wide HB vaccination programme. Such a situation may mean that these individuals may not be effectively protected against future HB infection. A booster dose of HB vaccine, given 18 years following HB vaccination, perhaps even earlier, should be considered.

Hepatitis B seroprevalence and anamnestic response amongst Taiwanese young adults with full vaccination in infancy, 20 years subsequent to national hepatitis B vaccination

The long-term protective effect of hepatitis B virus (HB) vaccination against HB infection and the necessity for routine booster vaccination in young-adult age subsequent to full HB immunization at birth remain issues of some debate currently. This study is aimed at evaluating the seroprevalence of HB infection and the response to HB booster vaccination amongst young-adult university students who had previously undergone full vaccination during their infancy. Eight hundred and forty-three subjects (mean age 18.7+/-0.4 years), 492 males and 351 females, with a complete HB vaccination during infancy were enrolled into this study. The prevalence of natural HB infection, chronic HB-carrier status, and HB-naïve group was, respectively, 4.1%, 1.4%, and 62.3%. Amongst 316 study subjects who were naïve to HB infection and had received one HB booster at time of university entrance health examination, 49.6%, 91.4%, and 97.5% of the participants with a serum anti-HBs level <0.1, 0.1 to <1.0 and 1.0 to <10.0mIU/mL prior to the booster vaccination, respectively, developed an anamnestic response (i.e., >/=10mIU/mL) to a booster dose of HB vaccine. Full implementation of national-wide HB vaccination program in 1986 has significantly reduced the incidence of HB infection and associated carrier rate in Taiwan. Approximately three-quarter of the subjects who were naïve to HB infection and had received one HB booster demonstrated an anamnestic response to a booster HB vaccine. The higher the anti-HBs titers remained for an individual subsequent to primary vaccination, the greater the anamnestic response observed. Additional long-term follow-up studies are needed for young adults initially vaccinated for HB in their infancy.

Timing of hepatitis B vaccination: its effect on vaccine response in health care workers

We assessed the effect of timing and other biological variables on immune response among health care workers (HCW) vaccinated with hepatitis B vaccine. A total of 2.058 HCW received three doses and were tested for anti-HBs within 6 months. 92.2% of the HCW had evidence of seroprotection. Multivariable analysis showed that controlling for age, the estimated non-response OR associated with a delayed second dose was 2.16 (95% CI: 1.46, 3.18, p=0.004). We found a decreasing response rate with increasing age. Particular attention should be given to those HCW who are late for the second vaccine dose and to older subjects.

Hepatitis B vaccination in women healthcare workers: a seroepidemiological survey

OBJECTIVE

To assess the concentration and kinetics of antibody response after hepatitis B vaccination among women healthcare workers.

DESIGN

Longitudinal retrospective seroepidemiological survey among women vaccinated against hepatitis B working in a university hospital and followed-up in an occupational health department. A structured form was used to collect socio-demographic characteristics, clinical data, age at vaccination, vaccination schedule, measurement of antibodies to hepatitis B surface antigen (anti-HBs antibody). Subjects were considered seronegative against hepatitis B when anti-HBs antibody concentration was less than 10 mIU/ml.

SETTING

A 1260-bed general hospital in Paris, France.

PARTICIPANTS

All women healthcare workers visiting the occupational health department between January 1997 1st and December 2000 31st and who had a measurement of anti-HBs antibody.

RESULTS

Irrespective of the age at the primary vaccination, 810 (92%) women were seropositive (anti-HBs antibody > or = 10 mIU/ml). Only 22 women (4.5%) vaccinated before 26 years of age were seronegative, against 46 (13.2%) vaccinated after 25 years of age (p < 0.001). Seven years after vaccination, 78% of women were still seropositive. An inadequate vaccination schedule (adjusted hazard ratio (HR), 3.0; 95% confidence interval [CI], 1.6-5.5) and an age greater than 25 years at primary vaccination (HR, 2.6; 95% CI, 1.5-4.4) were associated with being seronegative against hepatitis B.

CONCLUSIONS

Despite vaccination, some women healthcare workers were seronegative against hepatitis B virus. Vaccinating early in the career of a health-care worker using an adequate schedule seems key-elements to guarantee an anti-HBs measurement > or =10 mIU/ml.

Seroprevalence of Hepatitis-B infection amongst Taiwanese university students 18 years following the commencement of a national Hepatitis-B vaccination program

In Taiwan, the nation-wide Hepatitis-B virus (HB) vaccination program was first launched in July 1984 and was directed to those infants born to hepatitis B surface antigen (HBsAg) carrier mothers in Taiwan. From July 1986 onwards, all infants born in Taiwan were immunized against HB. This study examined the HB-infection status amongst students at a Taiwanese university 18 years subsequent to the implementation of universal HB vaccination. A total of 1,969 new university entrants in 2005 were grouped into 1 of 3 distinct birth cohorts according to their HB-vaccination schedule (cohort-1 students born prior to July 1, 1984; cohort-3 students born subsequent to June 30, 1986) and were examined for their serum HBsAg, antibody to hepatitis B surface antigen (anti-HBs), and antibody to hepatitis B core antigen (anti-HBc) status. Immunity arising from vaccination was defined as an anti-HBs level 10 mIU/ml. We observed a trend toward a decreasing anti-HBc-positive rate and a decreasing HBsAg carrier rate from, respectively, 26.5 and 8.7% for cohort-1 to 4.7 and 1.7% for cohort-3 students. The prevalence of students featuring seronegativity for all three HB markers increased from 12.3% for cohort-1 to 48.8% for cohort-3 individuals. Amongst the 1,695 subjects revealing seronegativity for HBsAg and anti-HBc, their anti-HBs level was analyzed according to their birth year. The prevalence of students featuring a non-protective anti-HBs level increased from 11.9% for birth-year 1984 individuals to 48.2% for birth-year 1987 students. The introduction of HB vaccine has effectively reduced the transmission of HBV infection in Taiwan, 18 years subsequent to the commencement of the universal HB-vaccination program. A "waning-off" effect of anti-HBs seropositivity acquired from the HB vaccination program has also been observed.

Hepatitis B virus among schoolchildren in an endemic area in Egypt over a decade: impact of hepatitis B vaccine

Cross-sectional studies were conducted over a decade among schoolchildren in an endemic area in Egypt for screening of hepatitis B (HB) virus markers. The significant decline of anti-HB core trend indicates the effectiveness of the prophylactic strategy in which the HB vaccine was incorporated. In addition, the persistence of protective titer of anti-HB surface among 54% of vaccinated children ages 6-10 years is encouraging. However, further investigations are recommended to clarify the unusual detected observations.

Evaluation of the clinical performance of the Beckman Coulter Access AbHBsII immunoassay for the detection of hepatitis B surface antibodies

BACKGROUND

Hepatitis B virus (HBV) surface antibodies (anti-HBs) testing is useful in various clinical circumstances, including identification of HBV susceptible individuals in pre- and post-vaccination programs.

OBJECTIVES

To assess the clinical performance of Beckman Coulter's anti-HBs chemiluminescence immunoassay (Access AbHBsII).

STUDY DESIGN

Laboratory performances were evaluated on 1207 routine samples pre-screened with Abbott Axsym anti-HBs assay and divided into three different panels: vaccinated subjects (n=232), subjects with resolved HBV infection (n=150) and negative subjects for anti-HBs (n=825). Sera with discrepant results were resolved by an alternative method and further chart review.

RESULTS

The overall concordance between Access and Axsym assays was 95.8%. The relative sensitivity, relative specificity, positive predictive value and negative predictive value were 97.8%, 98.1%, 96%, and 99%, respectively. Of the 51 discrepant results, eight were false negative by Access, fifteen were false positive by Access, including sera from seven pregnant women, two patients with acute leukemia, and four with inflammatory syndromes.

CONCLUSIONS

The Beckman Coulter's Access AbHBsII assay displays satisfactory relative sensitivity and specificity performances. The assay has good precision and reliability and is technically simple and fast.

Primary Hepatitis A vaccination failure is a rare although possible event: results of a retrospective study

A case of Hepatitis A occurred in a traveller in spite of a complete course of immunization with a combined HAV and HBV vaccine [Taliani G, Sbaragli S, Bartoloni A, Santini MG, Tozzi A, Paradisi F. Hepatitis A vaccine failure: how to treat the threat. Vaccine 2003;21(31):4505-6]. A retrospective study was performed to evaluate whether the failure was primary or could be attributed to a specific lot of vaccine or to its inadequate handling and/or storage. Two distinct populations of vaccinees were selected in a 1:2 proportion. The case group (N=31) included subjects who were vaccinated in the same period and with the same lot and batch of vaccine as the case. The control group (N=62) included subjects who received different lot and batch of the same vaccine as the case group. A persisting antibody response to HAV vaccine was found among all subjects (anti-HAV >20mIU/ml). The overall anti-HBs seropositivity rate (anti-HBs >10mIU/ml) was 74%, without significant difference between the case (77%) and the control group (73%; P>0.05). The reported Hepatitis A case can be attributed to a rare primary vaccine failure rather than to inefficacy of a specific lot of vaccine or to inappropriate vaccine handling or storage. Our study supports the indications for use of combined Hepatitis A+B immunization in travellers at risk for both infections, but stresses the need for information on correct hygienic behaviours while abroad.

Seropositivity for hepatitis B virus, vaccination coverage, and vaccine response in dentists from Campo Grande, Mato Grosso do Sul, Brazil

This study investigated the seropositivity for hepatitis B virus (HBV), the vaccination index, and the vaccine response index in dentists from Campo Grande, MS. Blood samples from 474 dentists (63.7% women and 36.3% men), with a mean age of 38.5 +/- 10.5 years were analyzed by enzyme-linked immunosorbent assay to detect the serological markers: HBsAg, anti-HBs, and anti-HBc. The HBsAg positive samples were tested for anti-HBc IgM, HBeAg, and anti-HBe. A total of 51 (10.8%) dentists showed seropositivity for HBV. Three (0.6%) were HBsAg/anti-HBc/anti-HBe positive, 43 (9.1%) were anti-HBc/anti-HBs positive, and 5 (1.1%) had only anti-HBc. Viral DNA was detected by polymerase chain reaction in 9 (17.6%) out of 51 HBV seropositive samples. A vaccination index of 96.6% (458/474) was observed, although 73.1% (335/458)completed the three-dose schedule. Excluding 46 HBV seropositive individuals from 458 that reported vaccination, 412 were analyzed for vaccine response index. It was observed that 74.5% (307/412) were anti-HBs positive; this percentage increased to 79.1% when three doses were administered. The results showed a high vaccination index and a good rate of vaccine response; however, the failure in completing the three-dose schedule and the occurrence of HBV infection reinforce the need for more effective prevention strategies.

Clinical safety and efficacy of a powdered Hepatitis B nucleic acid vaccine delivered to the epidermis by a commercial prototype device

This clinical delivery system bridging study evaluated the performance of a single-use disposable, commercial prototype device (designated ND 5.5) for particle-mediated epidermal delivery (PMED) of a nucleic acid vaccine against Hepatitis B virus (HBV). Healthy adults, previously immunized with licensed HBV vaccine, received a single boost vaccination of HBV nucleic acid vaccine administered by ND 5.5 or XR-1, the clinical research device used in previous clinical trials. Similar increases in anti-HBV surface antigen serum antibody titers and cell-mediated immune responses were produced by ND 5.5 and XR-1 when delivering comparable effective doses of the vaccine. The overall intensity of the immune response was lower in those subjects vaccinated with two, rather than 4 administrations of vaccine delivered by ND 5.5. Skin reactions at sites of vaccine administration were equivalent with both devices. This is the first clinical demonstration of the safe and effective PMED of a nucleic acid vaccine with the ND 5.5 device.

Long-term efficacy of hepatitis B vaccine, booster policy, and impact of hepatitis B virus mutants

The long-term efficacy of hepatitis B vaccine, long-term effectiveness of hepatitis B immunisation programmes, immune memory induced by hepatitis B vaccine, current booster policies, and impact of hepatitis B virus mutants on immunisation programmes were reviewed at the Viral Hepatitis Prevention Board (VHPB) meeting in Sevilla, Spain, March 2004. The main focus was on universal vaccination programmes with data being presented from Italy, Saudi Arabia, Singapore, Spain, Taiwan, Thailand, The Gambia, and USA (Alaska).

Compliance to hepatitis B vaccination and subsequent development of seroprotection among health care workers of a tertiary care center of Saudi Arabia

BACKGROUND

There is lack of reliable data on compliance to hepatitis B virus (HBV) vaccine and development of seroprotective levels of antibodies among health care workers (HCWs) from the countries with high HBV endemicity such as Saudi Arabia. This study aimed to assess the compliance with HBV vaccine and subsequent levels of seroprotection among HCWs of a large tertiary care center of the Eastern Province of Saudi Arabia.

METHODS

All the HCWs (n = 1302) involved in direct patient care, including 374 (28.7%) physicians, 619 (47.6%) nurses, and 309 (23.7%) technicians, were enrolled for the study. Those having antibody to hepatitis B surface antigens (anti-HBs) levels less than 10 mIU/mL were advised to take 3 doses of yeast-derived recombinant HBV vaccine at 0, 1, and 6 months of 1 mL (20 microg/mL) in the deltoid muscle. Blood samples were checked for anti-HBs antibody levels by enzyme immunoassay during the initial screening of HCWs and 3 months after the third dose of HBV vaccine. The group of physicians included 34.5% (129/374) of consultants, 16.8% (63/374) of specialists, and 48.6% (182/374) of residents.

RESULTS

An overall HBV vaccine compliance rate of 71.6% (932/1302) was observed among HCWs including that of 79.5% (492/619) among nurses, 78.3% (242/309) among technicians, and 52.9% (198/374) among physicians. Thus, physicians recorded the lowest compliance (OR, 3.211; 95% CI, 2.259-4.567; P < .0001) to HBV vaccine. Among physicians, the lowest compliance of 42.3% (77/182) was observed in residents (OR, 3.690; 95% CI, 1.067-3.703; P < .0001). The overall seroprotection after vaccination was achieved in 92.2% of the compliant HCWs, and 7.8% of them failed to mount adequate response to HBV vaccine. Nonresponders included mainly the physicians (OR, 2.229; P = .05)-consultants in particular (OR, 3.476; P < .0001). The mean age of nonresponders was higher than those who mounted an adequate anti-HBs response (46.7 +/- 6.3 vs. 32.2 +/- 3.3 years OR, 1.845; 95% CI, 0.999-3.414; P < .05).

CONCLUSIONS

Poor compliance to HBV vaccine among physicians--residents in particular-is an issue of immense concern, which demands close examination and identification of the specific action that needs to be taken to enhance the uptake of the vaccine by this target population.