Study to Assess the Safety and Effectiveness of Beltaven® in Patients With Allergy to Apis Mellifera, Polistes Dominula or Vespula Spp.

Inclusion Criteria: * Age 14 years or older at the time of study inclusion. * Written informed consent, duly signed and dated by the patient or by the legal representative in the case of minors. * Assent form duly signed and dated by the minor, when applicable. * Patients with allergy to Apis mellifera, Vespula spp., or Polistes dominula who have experienced a systemic reaction following a hymenoptera sting, either with involvement of multiple organs or exclusively cutaneous. * Positive intradermal test (mean wheal diameter ≥ 5 mm) with Beltaven® diagnostic (allergenic extract of Apis mellifera, Vespula spp., or Polistes dominula). * Positive specific IgE test from class 1 onwards (≥ 0.35 kUA/L). * Patients willing to receive immunotherapy with Beltaven®. Exclusion Criteria: * Patients with severe cardiovascular diseases, active malignant neoplasms or malignancies in remission within the last 5 years, non-stabilized systemic or organ-specific autoimmune diseases, severe mental disorders, or other relevant chronic diseases that may interfere with the study results. * Patients with known allergy to any of the vaccine excipients. * Pregnant patients, patients planning to become pregnant during the study period, or breastfeeding patients. * Patients who have received hymenoptera immunotherapy within the 5 years prior to inclusion or during the study. * Patients who are to receive immunotherapy with another specific allergen different from the investigational treatment during the study period. * Patients with confirmed sensitization to two or more hymenoptera species as demonstrated by CAP inhibition testing. * Patients with thrombocytopenic purpura and vasculitis, rhabdomyolysis, or renal failure.