[20 years' use of the diphtheria-pertussis-tetanus vaccine].

Between 1966 and 1982, a triple DPT vaccine was studied in France in 1,871 infants between the ages of 3 and 5 months. The study covered tolerance and serological efficacy of two immunization schedules using 2 or 3 initial injections. Computerized analysis of the 877 complete files showed satisfactory tolerance of this association and the serological efficacy of 2 initial doses of tetanus and diphtheria vaccines. Pertussis immunization is only effective after 3 injections. The presence of maternal antibodies when the first injection is given only decreases the immune response of diphtheria vaccine.