Evaluation of the two-needle strategy for reducing reactions to DPT vaccination.

Using a blinded crossover design, we tested the hypothesis that changing the needle on the syringe after drawing up diphtheria-pertussis-tetanus vaccine and before injecting it reduces local complications by eliminating deposition of aluminum phosphate adjuvant in the subcutaneous track of the needle. Two hundred twenty-three children (52.7%) received a two-needle vaccination while 200 (47.3%) received a one-needle vaccination. Three hundred forty-six parents (81.8%) returned a questionnaire reporting their child's reaction within 48 hours of injection. There was no significant difference in the occurrence of redness, swelling, tenderness, or limp or in parental measurements of redness and swelling between the one- and two-needle groups. Moreover, we found no differences in the frequency of systemic side effects, including fever, vomiting, anorexia, and crying. These results do not support the practice of changing needles to reduce diphtheria-pertussis-tetanus vaccine reactions.