Effectiveness of maintenance bee venom immunotherapy administered at 6-month intervals

Abstract

Extension of the intervals at which maintenance venom immunotherapy (MVIT) is administered has been attempted for many years. However, published evidence on its effect, especially in intervals of longer than 3 months, is sparse. To examine whether the administration of a bee venom (BV) maintenance dose at 6-month intervals is safe and efficacious. The 3-month intervals at which venom-allergic patients were receiving their MVIT were gradually extended to 6 months. Systemic reactions (SRs) to immunotherapy injections or to field stings were regularly recorded. Patients who were allergic to BV alone or also to other venoms were deliberately sting challenged by a honeybee after reaching the 6-month interval. The 3-month intervals were extended in 47 patients. A single patient (2%) developed an SR after receiving the injection at an interval of 4 months. Two field stings in 2 patients resulted in a mild SR in 1 patient. Of 14 sting-challenged patients, 3 (21%) developed an SR after the challenge. The 3 SRs occurred only among the 8 patients (38%) who were allergic to BV alone. The 3 patients with the SR to the challenge continued to receive the regular maintenance dose at monthly intervals 3 to 5 more times. Repeated sting challenges were then well tolerated in all 3 patients. The administration of MVIT at 6-month intervals does not provide suitable protection in BV-allergic patients, and they should continue MVIT at the accepted 1- to 3-month intervals.