Subcutaneous versus intramuscular injection for booster DT vaccination of adolescents

Abstract

The importance of the injection technique in booster vaccination was investigated in an open randomized study with 252 10-year-old Swedish school-children receiving routine DT vaccination either by subcutaneous or by intramuscular route in the upper arm. The adolescents had previously been primed with DT vaccine at 3, 5 and 12 months of age. Adverse reactions, monitored for 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). These 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 significant differences in antibody responses between the two administration routes were found in the 99 samples drawn 2 weeks after the booster. However, girls were found to have a lower response to diphtheria toxoid than boys ( p=0.009). Local reactions to a booster can thus be significantly reduced by choice of injection technique, which may be necessary if increased dosages and/or further valences are to be given to adolescents and adults.