BACKGROUND: The duration of protection after hepatitis B vaccination of infants is unknown. METHODS: We determined antibody to hepatitis B surface antigen (anti-HBs) at 4-13 years of age in 363 low risk children who had been vaccinated starting at birth with hepatitis B vaccine. Those with nonprotective titers ( or = 10 mIU/mL) of anti-HBs at 9 and 13 years, respectively. Of those who did not have protective antibody titers, 61% (33 of 54) and 67% (8 of 12), respectively, responded to a booster dose. In children of HBsAg-positive mothers, 31% retained protective anti-HBs at 12 years, and 90% (9 of 10) with nonprotective titers responded to a booster. In low risk children initially receiving a recombinant vaccine, 12.5% (26 of 208) and none (0 of 36) retained protective anti-HBs titers at 5 and 7 years of age, respectively. Of those who did not have protective titers, 90% (120 of 134) and 91% (32 of 35), respectively, responded to a booster. CONCLUSIONS: Anti-HBs disappeared by 5 years of age in most children who were vaccinated with hepatitis B vaccine from birth. Although most children showed immunologic memory, one-third failed to demonstrate an anamnestic response to a booster dose. Additional long term studies of low risk infants are needed to determine duration of protection and the necessity for or timing of booster doses.
To assess the clinical safety, reactogenicity and immunogenicity of an indigenously developed recombinant hepatitis B vaccine (Shanvac-B; Shantha Biotechnics) and to compare it with another commercially available vaccine (Engerix-B, SmithKline Beecham) in healthy adults.
120 healthy adults randomLy received 20 micrograms of either Engerix-B (Group A; n = 61) or Shanvac-B (Group B; n = 59) in 0, 1, 2 months schedule. Anti HBs was assessed using commercially available AUSAB kits (Abbott Laboratories) one month after each dose.
Protective seroconversion rates after first, second and third dose were 10%, 62.7% and 91.4%, respectively in Group A and 22.4%, 68.9% and 96.4% in Group B, respectively. The geometric mean titer (GMT) after the third dose was significantly high in Group B (419 mIU/mL) than in Group A (140 mIU/mL; p
This research project was conducted in the Ottawa-Carleton region of Ontario to provide information on reasons why students did not participate in a Grade 7 hepatitis B school immunization project, and to determine whether telephone contact increased attendance at the community catch-up clinics above that achieved by a notice sent home with the child from school. A matched comparison group design was used. The overall uptake of the first dose of the vaccine in the region was 94% of 8,560 eligible students; 90% were immunized at the school clinic and 4% at the community catch-up clinic. About 4% of the parents refused to have their child immunized at the school or catch-up clinics. Of parents in the intervention group 198 (95%) were contacted by phone. The major reasons for non-participation at the school clinics were: (1) the child was not at school on the clinic day, or the child was sick (51%), (2) there were problems with the consent form (21%), and (3) the parents did not know of the program (10%). More students from the intervention group (72%) came for vaccination than did those of the control group (50%) (p