Evaluation of a new combined inactivated DPT-polio vaccine.

A new combined DPT-Poliovirus vaccine (DPTP) has been developed in France. It contains the DPT components mixed with poliovirus antigens, prepared by culture on vero cells on microcarriers, inactivated by formalin and formulated at a level of 40-8-32 D-antigen units for the type 1, 2 and 3 respectively. A clinical evaluation of this vaccine was conducted in Mali (West Africa) among 320 infants 3 to 24 months of age. The infants were randomly assigned to 3 groups. One group received 2 doses of DPTP, a second group 2 doses of DPT and poliovirus vaccine (IPV) given in two separate sites, the third group 2 doses of DPT and oral poliovirus vaccine (OPV). In each group the 2 doses were given 3 months a part. No severe adverse reactions were observed and no statistical difference was noticed between the three groups for minor side effects. A seroconversion rate of 100% was observed to poliovirus antigens in the groups who received IPV simultaneously or combined with DPT, as compared to 49 to 77% in the group who received OPV. A seroconversion rate of 100%, 100% and 92% was shown in the DPTP group respectively to diphtheria, tetanus and pertussis antigens. No statistical difference was recorded between the 3 groups in the serological response to DPT antigens. A follow-up could be performed in 74 children one year after primary vaccination and a dramatic response to a booster dose of DPTP was measured.(ABSTRACT TRUNCATED AT 250 WORDS)