Deliberate bee sting challenge of patients receiving maintenance venom immunotherapy at 3-month intervals

A large part of the cost and inconvenience associated with venom immunotherapy (VIT) is related to the need for monthly treatments. Since VIT is advocated for at least 3 to 5 years, and occasionally longer, reducing the number of venom injections may cut down significantly on both cost and inconvenience.

We evaluated whether maintenance VIT given every 3 months is both safe and effective regarding reactions to treatment injections or field re-stings and lack of systemic reaction (SR) to deliberate challenge sting.

The standard 1-month interval was gradually extended to 3 months in 28 patients (mean age 26 years, range 7 to 76) allergic to bee venom (BV), yellow jacket venom, or both venoms. Nineteen patients allergic to BV were deliberately challenged by a live bee sting. In 15 patients the original SR in the field was moderate; in one patient it was mild; and in three patients it was severe.

Mean duration receiving standard maintenance VIT before extending the 1-month interval was 17 months. No patient had an SR while receiving the 3-month VIT therapy. Two patients experienced four field re-stings while receiving the 3-month therapy with no reaction. After the live challenge, there was mild urticaria in a single patient; no SR developed in the rest of the patients.

For young patients allergic to BV whose initial SR is mild to moderate and who have already received 1-month VIT for longer than 17 months, the maintenance interval may safely be extended to 3 months while preserving its protective activity against re-stings.