DEFINING THE KEY PARAMETERS FOR COMPARING REACTIONS AMONG ACELLULAR AND WHOLE-CELL PERTUSSIS VACCINES

Objective. To facilitate future vaccine reaction data collection and a nalysis, we sought to determine the minimum data set required to descr ibe accurately and to compare common reactions after the administratio n of acellular (DTaP) or whole-cell (DTP) pertussis vaccine with dipht heria and tetanus toxoids combined. Methods. Thirteen DTaP and 2 DTP v accines were studied in a multicenter trial involving 2342 infants who received a primary series of vaccinations at 2, 4, and 6 months of ag e. Temperature, fussiness, redness, swelling and pain at the injection site, antipyretic use, drowsiness, loss of appetite, and vomiting wer e evaluated. Reactions were assessed at 3 hours and (if not immunized in the evening) 6 hours after immunization, at bedtime each evening fo r 7 evenings, and on the 14th evening after immunization. Results. Two reaction assessment approaches were compared: (1) analysis of all rea ctions, regardless of the degree of severity; and (2) a condensation o f the data to five key reactions (fever > 100 degrees F, moderate or m ore fussiness, any local redness, any local swelling, and moderate or more local pain). We found that the onset of reactions was infrequent beyond the second evening, and that collection and analysis of reactio n data beyond that time did not further discriminate among the vaccine s. Information regarding antipyretic use, loss of appetite, drowsiness , or vomiting did not assist in differentiating among these vaccines. Conclusion. Monitoring the occurrence of fever greater than 100 degree s F, moderate or severe fussiness, injection site redness or swelling, and moderate or severe injection site pain occurring through the seco nd evening after immunization will provide the minimum data set needed to discriminate among DTaP and DTP vaccines with respect to the commo n adverse reactions.