In Reply.—We appreciate Dr Asnes' interest in our article on DPT reactions.
In referring to burrs on the tip of the needle, we assume that Dr Asnes is speaking of irregularities in the needle tip caused by passing the needle through the rubber stopper of the vaccine vial. Although we are unaware of any literature on this matter, and do not know if this occurs with any frequency, for the sake of argument we will assume that "virgin" needles are detectably sharper than those needles that pass through the stopper of the vial. The real issue here is whether this has any clinical significance for the patient.
To answer this question objectively one would have to measure pain at the time of injection in the one-needle and the two-needle groups. Since the population in the study ranges in age from 2 months to 6 years, measuring pain in this