DTaP Vaccine: Diphtheria, Tetanus, and Acellular Pertussis

Diphtheria, tetanus and pertussis (or whooping cough) are prevented by one combined vaccine, DTaP. Each of the three diseases was a major killer, so use of the combined vaccine became routine practice in the 1940s.

DTP, the early version of the present vaccine, often caused frightening side effects in infants and children, which in turn prompted vocal and organized opposition to the vaccine in this and other developed countries. In large part, DTP’s problem was that the pertussis component was produced by killing pertussis bacteria cells and then using the whole, killed cell in the vaccine. The whole-cell vaccine contained not only the parts of the bacteria that induced immunity, but also parts that caused fever and other side effects. For more than twenty years, scientists worked to identify and purify the exact parts of the cell that would induce immunity but not cause severe side effects. In 1981, a safer pertussis vaccine was licensed in Japan that did not contain whole cells; it was acellular .

Ten years later, in 1991, the first acellular pertussis vaccine was licensed for booster doses in the U.S. In 1996, DTaP was also licensed for the infant doses. By 1999, the acellular pertussis vaccine had been so widely accepted that ACIP and the American Academy of Pediatrics expressed their preference for this formulation by including only DTaP in the routine childhood immunization schedule. The marked decrease in demand for the older DTP is leading to its withdrawal from the market.

This information is excerpted from the book Vaccinating Your Child: Questions and Answers for the Concerned Parent (Peachtree Publishers, Ltd., 2000). The book’s authors are Dr. Sharon G. Humiston, a pediatrician and clinical researcher at the CDC and the University of Rochester, and Cynthia Good, an award-winning journalist and host of the television show “Good for Parents”.