Safety of supervised hospital vaccination in children at risk of hypersensitivity: A 9-year study

Introduction: Fear of allergic reactions is a frequent cause of vaccine hesitancy among families of children with allergic diseases. Vaccination in a supervised hospital setting is often recommended for children considered at increased risk of hypersensitivity. However, real-world data on the safety and impact of this approach in pediatric populations remain limited. Methods: We performed a retrospective, single-center study including children referred for vaccination under allergist supervision between July 2016 and May 2025. Vaccines were administered at full dose in a hospital setting, with predefined post-vaccination observation periods. Immediate and delayed adverse reactions were recorded using standardized criteria. Vaccination status and delays were assessed in relation to national age-appropriate immunization schedules. Results: A total of 180 children received 368 vaccine doses. Mean age was 4.2 years, and 62.2% were male. The main reasons for referral were food allergy and previous adverse events following immunization. Thirty-one children (17.2%) had a history of anaphylaxis, predominantly food-related. No cases of anaphylaxis or severe systemic reactions occurred during supervised vaccination. Mild, self-limited reactions were observed in five children (2.8%), accounting for 1.4% of vaccination visits. At referral, many children had delayed or incomplete immunization schedules. At the time of review, non-compliance was 28.9% for mandatory vaccines and 47.2% when mandatory plus recommended vaccines were considered; the median delay between vaccine prescription and supervised administration was 115 days. Conclusion: Supervised hospital-based vaccination is safe in children perceived to be at risk of hypersensitivity reactions, including those with previous anaphylaxis. A structured, allergist-led approach combining individualized risk assessment, standard-dose administration, and appropriate observation may facilitate completion of delayed immunization schedules and may help address vaccine hesitancy in allergic pediatric populations.