Immunogenicity and reactogenicity of two recombinant hepatitis B vaccines in small infants: a randomized, double-blind comparative study.

Hepatitis B infection is very common in infants, especially in countries with limited resources. Hepatitis B vaccination is recommended in the routine immunization schedules in many countries, including India. We compared immunogenicity and reactogenicity of two recombinant hepatitis B (HB) vaccines in healthy infants. A total of 262 evaluable Indian infants received three doses of 10 microg of an Indian (GeneVac-B) or European (Engerix-B) HB vaccine in a double-blind, randomized fashion. The first dose, given at birth, was followed by a dose at age 6 and 14 weeks. All the subjects were initially seronegative for HB surface antigen (HBsAg) and anti-HB antibodies (anti-HBs). The post-vaccination anti-HBs titers were assessed by ELISA at the time of second and third dose, and 1 month after the third dose. Seroconversion and seroprotection were defined as anti-HBs titers > or =1 mIU/ml and > or =10 mIU/ml, respectively. After first dose, the seroconversion rates were 20% and 17%, in Indian and European vaccine recipients, respectively. The second and third dose increased the seroconversion to 84% and 80%, and to 98% and 98%, respectively. Correspondingly, the seroprotection rates after the first dose was 11% and 10%, and consequently 54% and 58%, and 97% and 95%. None of the differences between vaccines reached statistically significant proportions. Geometric Mean Titer after third dose was 383 mIU/ml and 285 mIU/ml, respectively, also this difference remaining insignificant. Adverse events were similar in both vaccine groups. Immunogenicity and reactogenicity of the Indian and European Hepatitis B vaccines were comparable, when immunization was started at birth.