EVALUATION OF IMMUNOGENICITY AND SAFETY OF GENEVAC B: A NEW RECOMBINANT HEPATITIS B VACCINE IN COMPARISON WITH ENGERIX B AND SHANVAC B IN HEALTHY ADULTS

Effectiveness of hepatitis B vaccination in chronic HCV patients after successful generic direct acting antiviral therapy: significance of isolated hepatitis B core antibodies

OBJECTIVE

Previous reports show conflicting results regarding hepatitis B virus (HBV) vaccine efficacy in Hepatitis C virus (HCV) infected individuals and in those with isolated hepatitis B core antibodies (HBcAb). We aimed to evaluate the effectiveness of HBV vaccine and identify possible factors that may contribute to hyporesponsivness in HCV-treated patients, including those with isolated HBcAb.

METHODS

We conducted a prospective study with 118 enrolled chronic HCV patients who followed a 12-week regimen of direct acting antivirals (DAAs) and were evaluated for HBV serological markers. Eventually, 98 received appropriate HBV vaccination and were assessed for response.

RESULTS

A total of 57.1% were vaccine responders although only 5.1% achieved a seroprotective level of HBsAb titre. The response rate was significantly lower among treated HCV patients with isolated HBcAb [2 (5.6%) vs. 40 (64.5%) respectively]. On multivariate analysis, advanced age [OR (95% CI) = 1.09 (1.02-1.17)] and presence of isolated HbcAb [OR (95% CI) = 39.59 (7.98-196.63)] were predictors of vaccine non-response. In our cost-effectiveness models, the cost of HBV serological screening was less than the nationally adopted non-screening approach. A model ratifying reinforced vaccination in non-responder HBcAb seropositive HCV patients would incur extra cost.

CONCLUSION

Hyporesponsiveness to the HBV vaccination is frequent in chronic HCV patients even after achieving SVR following DAAs. Although there is no consensus on the clinical management of patients with isolated HBcAb, our cost-effectiveness options may support decision-making for better clinical benefit and proper health investments.

Prevalence of non-responsiveness to an indigenous recombinant hepatitis B vaccine: a study among South Indian health care workers in a tertiary hospital

BACKGROUND AND AIM

Health care workers (HCW) are at higher risk of contracting HBV infection. Non-response to HBV vaccine is one of the major impediments to prevent healthcare associated HBV infection (HAHI). We estimated the prevalence of non-responsiveness to initial 3-dose regimen of an indigenous recombinant HBV vaccine (GeneVac-B) among South Indian HCWs and typed the HLA in non-responders.

STUDY DESIGN AND METHOD

Of the 778 subjects screened over 1 year, 454 completed all three doses of the hepatitis B vaccination. Anti-HBs titers were estimated by microparticle enzyme immunoassay AxSYM AUSAB, (Abbott, Germany). HLA typing was done using SSP-PCR assay AllSet+™ Gold SSP (Invitrogen, USA).

RESULTS

The overall seroconversion rate (anti-HBs>10 mIU/mL) was 98.89% wherein 90.8% had titers>1000mIU/mL, 7.6% had titers 100-1000mIU/mL, 0.43% had titers<100 mIU/mL and 1.1% were non-responsive (<10 mIU/mL) to the initial 3-dose regimen. Antibody titers<1000 mIU/mL were significantly associated with the highest quartile of body mass index (BMI) (P<0.001). We found no significant difference in seroprotection rate between gender (P=0.088). There was no difference in seroprotection rates among various ethnic groups (P=0.62). Subjects who were non-responsive in our study had at least one HLA allele earlier known to be associated with non-responsiveness to the vaccine.

CONCLUSION

Our findings suggest that non-response to HBV vaccine is not a major impediment to prevent HAHI. Robust seroprotection rates can be achieved using this indigenous HBV vaccine. However, gender and BMI might influence the level of anti-HBs titers. We recommend the use of this cost effective HBV vaccine as well as postvaccination anti-HBs testing to prevent HAHI among HCWs.

Adult immunization in India: Importance and recommendations

Vaccination is recommended throughout life to prevent infectious diseases and their sequelae. Vaccines are crucial to prevent mortality in that >25% of deaths are due to infections. Vaccines are recommended for adults on the basis of a range of factors. Substantial improvement and increases in adult vaccination are needed to reduce the health consequences of vaccine-preventable diseases among adults. Incomplete and inadequate immunization in India against these communicable diseases results in substantial and unnecessary costs both in terms of hospitalization and treatment. The government of India as well as the World Health Organization (WHO) consider childhood vaccination as the first priority, but there is not yet focus on adult immunization. Adult immunization in India is the most ignored part of heath care services. The Expert Group recommended that data on infectious diseases in India should be updated, refined, and reviewed periodically and published regularly. This group suggested that the consensus guidelines about adult immunization should be reviewed every 3 years to incorporate new strategies from any emerging research from India. There is an immediate need to address the problem of adult immunization in India. Although many issues revolving around efficacy, safety, and cost of introducing vaccines for adults at the national level are yet to be resolved, there is an urgent need to sensitize the health planners as well as health care providers regarding this pertinent issue.

Brazilian hepatitis B vaccine: a six-year follow-up in adolescents

The protective anti-HBs titres were examined six-year post-immunisation with the Brazilian recombinant hepatitis B vaccine. After the primary vaccination, all adolescents (n = 89) responded with protective anti-HBs titres and had a geometric mean titre (GMT) of 4031.8 mIU/mL. In 2010, 94.5% maintained protective anti-HBs (> 10 mIU/mL) antibodies, with a GMT of 236.0 mIU/mL. A positive correlation was observed between the anti-HBs titres after the primary vaccination and the titres at the six-year follow-up (p < 0.01). Eleven subjects showed anti-HBs titres suggestive of a natural booster. Prostitution and tattoos/piercings were marginally associated with natural boosters in the multivariate analysis. This study showed the first data on anti-HBs persistence following the Brazilian hepatitis B vaccine in sexually active individuals and highlights its effectiveness in the medium term.

Relationship between T-lymphocyte cytokine levels and sero-response to hepatitis B vaccines

AIM: To investigate the cellular defects by analyzing the (Th1/Th2) cytokine levels in vaccine responders and non-responders.

METHODS: Peripheral blood mononuclear cell (PBMC) from responders and non-responders were stimulated with or with out recombinant HBsAg or PHA. Broad spectrum of cytokines viz (Th1) IFN-γ, IL-2, TNF-α, IL-12 and (Th2) IL-10, IL-4 were measured after in vitro stimulation with recombinant HBsAg and were compared with respective antibody titers.

RESULTS: A significant decrease (P = 0.001) in Th1 and Th2 cytokines namely, IL-2, INF-γ, TNF-α and IL-10 in non-responders was observed. The level of IL-4 was not significant between the three groups. Furthermore, despite a strong Th1 and Th2 cytokine response, the level of IL-12 was elevated in high-responders compared to other groups (P = 0.001) and demonstrated a positive correlation with anti-HBs titers and Th1 cytokine response.

CONCLUSION: Our findings suggest that unresponsiveness to recombinant hepatitis B vaccines (rHB) is multifactorial, including specific failure of antigen presentation or the lack of both T helper Th1 and Th2 response.

Comparative efficacy of two dosages of recombinant hepatitis B vaccine in healthy adolescents in India

BACKGROUND

Inclusion of hepatitis B vaccine in the Universal Programme of Immunization of all Asian and African countries is hampered by the economic burden on the health budget because of the cost of hepatitis B vaccines. Here we evaluated the immunogenicity, safety, efficacy, and the persistence of antibody to hepatitis B surface antigen (anti-HBs) titers of a new and a low cost recombinant hepatitis B vaccine GeneVac B, with 2 different dosages in healthy adolescents in India.

METHODS

GeneVac-B, a recombinant hepatitis B vaccine (Serum Institute of India, Pune, India), was administered in 10 or 20 microg dose intramuscularly to 2 groups of 100 healthy school-going adolescents at 0-, 1-, and 6-month intervals, who were followed up for 1 year. Group I received 20 mug doses whereas Group II received 10 mug doses. Blood samples were collected 1 month after each dose and 1 year after the third dose. The anti-HBs titers were assayed using commercially available kits to assess the immunogenicity of the 2 dosage schedules. Safety studies were also carried out.

RESULTS

The geometric mean titer value of the anti-HBs titer 1 month after the third dose was 2629 (mlU/mL) in Group I and 1373 mlU/mL for Group II subjects. One year after the third dose, the persistence of anti-HBs in those who had received 20 mug was 2262 mlU/mL whereas it was 1039 mlU/mL in the group receiving 10 microg doses. All the subjects in both the groups were seroprotected at 1 year after vaccination. None of the vaccinees exhibited serious adverse reactions throughout the study period.

CONCLUSIONS

The study demonstrated the immunogenicity of the recombinant hepatitis B vaccine, and confirms that the 0.5 mL (10 microg) dose of GeneVac B can be administered with satisfactory safety and immunogenicity to adolescents up to 19 years of age, reducing the cost to less than U.S. $1.00 per dose making it acceptable for the Universal Programme of Immunization of developing and under developed countries.

Comparison of two hepatitis B vaccines (GeneVac-B and Engerix-B) in healthy infants in India

Hepatitis B is a major problem in many parts of the world. The WHO has recommended the inclusion of hepatitis B vaccines in routine immunization schedules. We wanted to compare two recombinant hepatitis B vaccines in an infant population for immunogenicity and reactogenicity when given at 6, 10, and 14 weeks of age. One hundred seventy-three infants meeting eligibility criteria were given either GeneVac-B (Serum Institute of India Ltd.) or Engerix-B (GlaxoSmithKline Beecham) in a random fashion. Three 0.5-ml (10-mug) doses of the vaccines were given at 6, 10, and 14 weeks of age along with diphtheria-pertussis (whole cell)-tetanus (DTPw) vaccine. Blood samples were collected at baseline and 1 month after administration of the third dose of the vaccines to measure anti-HBs antibody levels. Seroconversion was defined as a titer of more than 1 x 10(-3) IU/ml, while seroprotection was defined as a titer of more than 10 x 10(-3) IU/ml. Of the GeneVac-B recipients, 98% seroconverted versus 99% of the Engerix-B group. The anti-HBs geometric mean titer was slightly greater for GeneVac-B (229 x 10(-3) IU/ml) than for Engerix-B (167 x 10(-3) IU/ml), but the difference was not significant. The seroprotection rates were similar for both vaccines (96% and 95%, respectively). The most common systemic reaction events were mild to moderate fever, excessive crying, local swelling, rash, and irritability, and the local reactions were redness, induration, and edema, which most probably were caused by the simultaneously administered DTPw vaccine. All events were transient and resolved without sequelae. Reactogenicity was similar for the two vaccines. The present study shows that GeneVac-B is as immunogenic and as well tolerated as Engerix-B when administered with DTPw vaccine at 6, 10, and 14 weeks of age.