Children have reactions to the diphtheria and tetanus toxoids and pertussis vaccine (DTP), but whether they have serious reactions is a matter of dispute, definition, and, perhaps, intention. The articles by Rosenthal et al1,2 concerning the safety of whole-cell vaccine and the newly licensed acellular vaccine mentioned the word "serious" many times: reactions were characterized as serious, serious adverse, and, as a variation, severe events. Because more serious neurologic events were not reported in the prelicensure trials of the new acellular vaccines, Rosenthal et al have pursued reputed serious reactions from a much larger database, that of the United States, the largest denominator in the industrialized world.
It has been, and still is, the position of the Centers for Disease Control and Prevention, Atlanta, Ga, and the National Childhood Vaccine Injury Act that acute encephalopathy can rarely follow DTP vaccination. Yet, in this study of the United States from