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 μg 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 μg doses whereas Group II received 10 μg 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 μg was 2262 mlU/mL whereas it was 1039 mlU/mL in the group receiving 10 μg 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 μg) 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.