Safety and immunogenicity in young infants of Haemophilus b-tetanus protein conjugate vaccine, mixed in the same syringe with diphtheria-tetanus-pertussis-enhanced inactivated poliovirus vaccine.

Because inactivated poliovirus vaccine (IPV) and Haemophilus influenzae b vaccine are advised in many programs and may be incorporated further in other programs, we undertook a study to determine whether the administration of a tetravalent preparation of diphtheria-tetanus-pertussis-IPV mixed in one syringe with tetanus-conjugate H. influenzae b vaccine (DTP-IPV-PRPT) is associated with increased reactogenicity or interference with immunogenicity of individual vaccine components. In a placebo-controlled, double blind study, a total of 161 infants were enrolled (80 DTP-IPV-PRPT and 81 DTP-IPV-placebo). Vaccine was administered at 2, 4 and 6 months of age. Oral poliovirus vaccine was added at 7 months of age and a booster of oral poliovirus vaccine and DTP-IPV was also administered at 12 months of age, according to the policy in Israel. Local and systemic side effects were similar in both groups except for irritability after the second dose and use of acetaminophen which we observed slightly but significantly more often in the DTP-IPV-PRPT recipients. After the third dose the geometric mean titers of anti-polyribosyl-ribitol phosphate antibodies were 3.7 and 0.05 micrograms/ml in the PRPT and placebo groups, respectively (P < 0.001). Higher tetanus antitoxin titers were observed among recipients of DPT-IPV-placebo (1.1 IU/ml vs. 0.7 IU/ml, P = 0.003). A similar trend was found for pertussis agglutinin titers (93.4 vs. 65.4, P = 0.054). No difference was observed for anti-diphtheria toxoid and poliovirus 1, 2, and 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Safety and immunogenicity of Haemophilus type b-tetanus protein conjugate vaccine, mixed in the same syringe with diphtheria-tetanus-pertussis vaccine in young infants.

As new vaccines are developed there is increasing interest in reducing the number of injections given to children by combining vaccines in one syringe. We studied the safety and immunogenicity of Haemophilus influenzae type b-tetanus protein conjugate vaccine (PRP-T) administered at ages 2, 4 and 6 months mixed in the same syringe with DTP vaccine and its effects on the seroresponse to DTP vaccine. A group of 112 healthy 2-month-old infants received DTP-PRP-T or DTP-placebo mixed immediately before immunization in the same syringe. The addition of PRP-T to DTP did not increase the rate of local or systemic reactions. After the first, second and third dose, the PRP-T recipients showed a geometric anti-PRP antibody mean of 0.13, 2.31 and 6.40 micrograms/ml vs. 0.07, 0.05 and 0.05 micrograms/ml among the DTP-placebo recipients, respectively. Of the PRP-T recipients, 94 and 98% attained antibody concentration of greater than or equal to 0.15 micrograms/ml protein after the second and third dose, respectively, and 65 and 94% attained a concentration of greater than or equal to 1.0 micrograms/ml after the second and third dose, respectively. At the age of 1 year 94 and 52% of the DTP-PRP-T recipients vs. 12% and 0% of the placebo recipients still maintained titers of greater than or equal to 0.15 and greater than or equal to 1.0 micrograms/ml, respectively. The administration of DTP in the same syringe with PRP-T did not affect significantly the antibody response to diphtheria and tetanus toxoid and to pertussis agglutinins. It is concluded that PRP-T vaccine could be administered in the same syringe as DTP.