A 5‐year venom immunotherapy protocol with 50 μg maintenance dose: safety and efficacy in school children

Abstract

Venom immunotherapy (VIT) has been shown to be an effective and safe treatment for preventing sting-induced anaphylaxis in patients with systemic reactions to hymenoptera stings. A remaining problem is the relative effectiveness and safety of different immunotherapy protocols used with respect to maintenance dose, injection interval, and duration. We aimed to describe a modified cluster VIT protocol with a maintenance dose of 50 μg lasting 5 yr and to evaluate retrospectively its safety and efficacy in children. Fifty four children 9.5±3.2 yr old with a history of at least one anaphylactic reaction to hymenoptera stings underwent VIT between 1995 and 2006. The identification of the offending insect(s) was based on patient's report and documented with in-vivo (SPTs and IDs) and in-vitro (RAST/CAP) test results. A modified cluster outpatient protocol lasting 5 wks, reaching a maintenance dose of 50 μg was followed according to clinical history and test results. After the maintenance dose was achieved, the followed injection-intervals were 4 wks for the first year, 5 wks for the 2nd year and 3rd year, and 6 wks for the last 2 yr. Of the 54 children, 52 tolerated the 50 μg VIT protocol without side effects. Twenty one of them reported at least one field sting from at least one of the culprit, for their allergy, insects, 6±3.5 yr after they have started VIT treatment. In 11 of them, sting occurred 3.5±2.9 yr after the VIT was completed, whereas the other 10 of them during immunotherapy, 3.2±1.4 yr after they have started VIT. In the remaining two children, the maintenance dose was increased to 100 μg due to systemic reactions from the VIT. The data reflect outcomes 6-16 yr after the patients' initial allergic reaction. VIT with 50 μg maintenance dose lasting 5 yr appears to be safe and effective enough to induce tolerance in children with hymenoptera venom hypersensitivity.