Grant: Planning and Dissemination Grants - Institute/Initiative Community Support

Penicillin allergy is one of the most common drug allergies reported worldwide, affecting nearly one in ten patients. However, studies show that over 90% of these individuals can safely receive penicillin after proper allergy testing. Mislabeling someone as allergic leads doctors to prescribe alternative antibiotics, which are often less effective, more expensive, and contribute to antibiotic resistance and longer hospital stays. The PROSPECTOR-2 trial (PROlonged versus Single dose in PEnicillin oral Challenge Testing double-blind parallel randomized placebo-controlled tRial) is a large international study designed to determine whether a single dose of penicillin is sufficient to rule out delayed allergic reactions, or if a five-day (prolonged) test is needed for greater accuracy. This question is especially important for patients whose previous allergic reaction occurred long ago or was not clearly documented. The study involves 13 hospitals across five continents (Canada, Australia, Denmark, Belgium, South Africa, and Hong Kong). It represents the first global double-blind randomized trial of its kind, using standardized procedures and centralized data collection to ensure scientific and ethical rigour. To coordinate this extensive network, investigators will meet in person during the Drug Hypersensitivity Meeting 2026 (DHM 2026) in Belgium. The meeting will align all study sites on recruitment, safety monitoring, and data quality, thereby strengthening international collaboration. By enhancing global coordination, the PROSPECTOR-2 project will facilitate the establishment of safer and more reliable testing for penicillin allergy, reduce unnecessary allergy labels, and promote better antibiotic use worldwide.