ABSTRACT
The Heberbiovac-HB recombinant hepatitis B vaccine was administered at dosages of 10.5 and 2.5 micrograms in 3 groups of children aged 6-9 with a vaccination schedule at 0, 1 and 6 months of age. The immunogenecity attained between dosages was compared. The seroconversion with protective titres obtained at 2 months varied from 88.9 with 10 micrograms to 79.4 with 2.5 micrograms, whereas at 7 months it was higher than 98 in the 3 groups. The geometrical mean with 10 mg was 136.63 and 2,356.8 UI/L-1; with 5 micrograms, 77.62 and 1,958.9 UI/L-1; and with 2.5 micrograms, 32.15 and 376.3 UI/UL-1, at 2 and 7 months, respectively. A high immunogenic power of the vaccine is observed at dosages of 10 and 5 micrograms with similar results. In spite of the fact that the dosage of 2.5 micrograms is immunogenic, the response is not desirable. These results state the possibility of using a lower dosage (5 micrograms) for a low risk infantile population, which favors the cost-benefit.