Abstract : BACKGROUND Immunization is the best method of protection against hepatitis B. Routine vaccination f
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Abstract : BACKGROUND Immunization is the best method of protection against hepatitis B. Routine vaccination for newborns and infants was introduced in Poland in 1994-96. Although duration of protection afforded by vaccination remains unknown no routine boosters are recommended. According to references up to 50 of 15-year old children had lost the post vaccination immune memory protecting against HBV infection. The aim of the study was to determine the immunity against hepatitis B in 10-12-year old children and to establish indications for routine booster doses.|MATERIAL AND METHODS In 130 children aged 10-12 years immunized against hepatitis B with recombinant vaccine in infancy (10 microg according to schedule 0-1-2-12 months first dose given at birth) humoral immunity (anti-HBs antibodies) as well as cellular memory (anamnestic response to booster given in children without protective titers of anti-HBs) were determined. Titers of anti-HBs gt or = 10 IU/l were considered protective. Anamnestic response was defined as increase in anti-HBs concentration from lt 10 IU/l to gt or = 10 IU/l 4 weeks after receiving a booster dose. MARKERS OF HBV INFECTION hepatitis B surface antigen (HBsAg - marker of chronic hepatitis) and antibodies to core antigen (anti-HBc--marker of past HBV infection) were additionally determined.|RESULTS Protective level of anti-HBs was found in 102/130 (78) children including 43/130 (33) with high (100-999 IU/l) and 16/130 (12) with very high (gt or = 1000 IU/l) titers. 28/ 130 (22) did not have protective level of anti-HBs in 9/130 (7) antibodies were undetectable. Immune memory was determined in 9 children--anamnestic response was revealed in eight of them (89). In 6/130 (4.5) of participants HBV infection was confirmed according to positive anti-HBc including 2 (1.5 of the study group) with positive HBsAg.|CONCLUSIONS: Most children in the studied group had seroprotection and immune memory against hepatitis B 10-12 years after vaccination. No routine booster seems to be necessary.|
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