Subcutaneous versus intramuscular injection for booster DT vaccination of adolescents

The importance of the injection technique in booster vaccination was invest igated in an open randomized study with 252 10-year-old Swedish school-chil dren receiving routine DT vaccination either by subcutaneous or by intramus cular route in the upper arm. The adolescents had previously been primed wi th DT vaccine at 3, 5 and 12 months of age. Adverse reactions, monitored fo r 2 weeks, showed the same low rates for systemic reactions in both groups, while the intramuscular administration gave significantly less redness (p < 0.001), swelling (p <: 0.001), itching (p < 0.01) and pain (p < 0.05). Th ese reactions were also of shorter duration (p < 0.01 to p < 0.001). Girls were found to have more pain and itching than boys (p < 0.001). No signific ant differences in antibody responses between the two administration routes were found in the 99 samples drawn 2 weeks after the booster. However, gir ls were found to have a lower response to diphtheria toroid than boys (p = 0.009). Local reactions to a booster can thus be significantly reduced by c hoice of injection technique, which may be necessary if increased dosages a nd/or further valences are to be given to adolescents and adults. (C) 1999 Elsevier Science Ltd. All rights reserved.