RESUMO
The study was conducted on 60 infants born to hepatitis B surface antigen [HBsAg] negative mothers. Their gestational age ranged from 32 to 40 weeks [36 +/- 2.8] and their birth weight ranged from 1250 to 3800 gm [X2345 +/- 885]. Assessment of the seroprotection of these infants after hepatitis B virus [HBV] vaccination [at 2, 4 and 6 months of age] and its relation to prematurity, birth weight and medical problems as respiratory distress syndrome [RDS], blood transfusion, steriod treatment and sepsis, on seroconversion was done, anti-HBs antibody levels were measured one month after the third dose of vaccine [at 7 months of age]. Hepatitis B seroprotection could be obtained in 100% of infants with birth weight of 1500 gm or more. Very low birth weight [VLBW] infants [< 1500 gm] seroprotection was 3 7.5% which is unacceptably high due to severe immaturity of the immune system. Lower gestational age, sepsis, respiratory distress syndrome [RDS], treatment with steroids or infants who had a history of blood transfusion were associated with poor seroprotection rates [33.32%, 33.3%, 66.7%, 66.6% and 66.7% respectively]. It may be concluded that, premature infants of birth weight < 1500 gm, and who suffered from RDS, sepsis, received blood transfusion or had been treated with steroids, their anti-HBs antibody level must be checked after the age of 7 months to decide if they are in need of a booster dose of HBV vaccine or not