Use of a 25-mm needle was associated with less risk of redness and pain than was use of a 16-mm needle among children receiving their fifth diphtheriatetanus-acellular pertussis vaccine, according to results from a prospective randomized trial.

The results also suggested that the thigh should be considered as the site for the fifth injection, the investigators reported.

Dr. Lisa A. Jackson of the epidemiology department of the University of Washington, Seattle, and colleagues reported results from 1,315 pediatric patients (median age 54 months) in a study funded by Sanofi-Pasteur Inc.

Most (1,174 patients) received the vaccination in the arm; 141 were injected in ...