On Aug. 21, 1992, the Food and Drug Administration (FDA) approved licensure of a second DTaP product, prepared and distributed as Tripedia\T by Connaught Laboratories (Swiftwater, Pennsylvania).

As with ACEL-IMUNE\T, Tripedia\T is licensed only for use as the fourth and/or fifth dose(s) for children aged 15 months through 6 years (i.e., before the seventh birthday) who have previously been vaccinated against diphtheria, tetanus, and pertussis with three doses of whole-cell diphtheria and tetanus toxoids and pertussis vaccine (DTP) and is not licensed for the initial three-dose series in infants and children; whole-cell DTP should continue to be used for these initial doses.

Whole-cell DTP continues to be an acceptable alternative for the fourth and/or fifth dose(s).