Diphtheria, tetanus and whole cell pertussis vaccine combined with hepatitis B vaccines: A comparison of two doses (10 μg and 5 μg)

Background. A combined diphtheria-tetanus-whole cell pertussis-hepatitis B (DTPwHB) vaccine might facilitate the achievement of universal vaccination of infants against hepatitis B. Methods. A double blind, randomized, two- armed, single center study was undertaken to evaluate the immunogenicity and reactogenicity of combined tetravalent DTPwHB vaccine, with two dosages of hepatitis B component (10 μg and 5 μg). The combined vaccine was tested in the context of a simplified vaccination schedule at 1.5, 3.5 and 6 months of age, to 120 healthy infants born to hepatitis B surface antigen-negative mothers after priming with one dose of hepatitis B vaccine (10 μg) at birth. Antibodies to each antigenic component were measured from blood samples collected immediately after birth, pre-and postvaccination blood samples. Results. The reactogenicity profiles were similar in the two groups. No serious adverse events were reported. One month after completion of the four- dose vaccination schedule, all subjects except one in Group 1(10 μg) had protective titers of anti-HBs (10 mIU/ml). At this time the geometric mean titer in Group 1 (10 μg) was higher than that observed in Group 2 (5 μg), 696 vs. 488 mIU/ml (P = 0.19). One month after three doses all subjects in both groups had protective antidiphtheria titers and antitetanus titers. The vaccine response rate to the Bordetella pertussis component of the vaccine was 88.0% in Group 1 and 96.2% in Group 2 (P = 0.86). Conclusion. Both combined tetravalent vaccines are safe and immunogenic when administered to infants born to a hepatitis B surface antigen-negative mother, with a 10-μg dose of priming hepatitis B vaccine at birth. This combined tetravalent DTPwHB vaccine may play an important role to promote integration of HB vaccine into the Expanded Program of Immunization in hepatitis B-endemic areas.