RESUMEN
The efficacy of two different doses [2.5 and 5meg] of Hepatitis B [Recombinant DNA] vaccine was tested in 20 healthy full term infants born to HBs Ag negative mothers. They were vaccinated at 0, 1 and 6 months. HBs antibody levels were measured using ELISA. technique in sera of mothers and, their corresponding infant prior to vaccination and repeated in infants 2 months after the last dose. The vaccine was well tolerated in either doses without local or systemic adverse reactions. The antibody response was comparable both in i:nmune infants born to HBs Ab positive mothers and non-immune ones born to HBs Ab negative mothers. HBs Ab level was 92.5 mlu/ml when the reduced dose [2.5 mcg] of the vaccine was given compared to 88.3 mlu/ml with 5 meg dose [P > 0.05] indicating comparable antibody response. We concluded that smaller doses of 2.5 meg could be used safely in mass vaccination of infants against hepatitis B infection