- D1.522 - Efficacy of hymenoptera venom immunotherapy in Portugal: a systematic review

Venom immunotherapy (VIT) remains the only treatment that can potentially prevent further systemic sting reactions in patients allergic to hymenoptera venom. Variations in extract availability and treatment protocols across European countries, may influence both its safety and efficacy. We aimed to review the reported efficacy of VIT in Portugal.

Subanalysis of the systematic review study of hymenoptera venom allergy in Portugal (PROSPERO CRD420251087328), focusing on the efficacy of VIT. Original publications in full-text, abstract, or theses, published up to December 31^st, 2024, were selected. Of the 69 included studies, those reporting data on the efficacy of VIT in at least one patient were subsequently analysed.

A total of 212 patients from 13 retrospective case series were included (1 to 38 patients per publication). All reported field stings, with 84-85% efficacy for honeybee venom (n=74), 100% for vespids (n=44), and 87-88% in studies where the culprit hymenoptera was not reported (n=94). VIT was performed using aqueous extracts and a maintenance dose of up to 100μg. Systemic reactions to VIT, positive sIgE to Api m 4, and negative/low sIgE to Api m 10 were potentially associated with a higher frequency of systemic reactions to field stings.

The results of the current review suggest that hymenoptera venom immunotherapy is effective, with the aqueous extracts available in Portugal. A larger, multicentric study reporting the outcomes of the sting challenge test is needed to confirm efficacy and to evaluate possible risk factors for hymenoptera venom immunotherapy failure.