Epidemiology of Pediatric Transfusion Reactions.

Importance: Pediatric hemovigilance is a nascent field in transfusion medicine. The lack of standardized hemovigilance reporting in the US makes it difficult to determine age-specific transfusion reaction rates and risks. Objective: To evaluate the rates and epidemiology of transfusion reactions reported to transfusion services in neonatal and pediatric populations. Design, Setting, and Participants: This cohort study analyzed transfusion reactions occurring in children younger than 18 years reported to 8 hospitals' transfusion services during April 1, 2019, through December 31, 2023. Data were evaluated from March 2024 to June 2025 using standardized data collection forms and associated electronic health records. Exposure: Patients who received transfused blood products (red blood cells [RBCs], platelets, plasma, or cryoprecipitate) with at least 1 transfusion reaction reported to the transfusion service. Main Outcomes and Measures: Reaction rates per 100 000 products transfused were calculated. Pediatric transfusion reactions were characterized in detail, including reported severity and imputability; product type; patient age, sex, race, and ethnicity; and reported symptoms, premedication, and clinical management. Results: The sample included 228 886 products transfused to 22 628 patients (median [IQR] age, 4.2 [0.3-12.4] years; 127 903 males [55.9%]). The products were transfused to patients of Asian (18 649 [8.2%]), Black (37 673 [16.5%]), White (93 824 [41.0%]), multiracial (3680 [1.6%]), other (68 857 [30.1%]), or unknown race (6203 [2.7%]) and Hispanic or Latinx (52 398 [22.9%]), non-Hispanic and non-Latinx (144 017 [62.9%]), and unknown ethnicity (32 471 [14.2%]). A total of 1165 imputable transfusion reactions were reported, with an overall reaction rate of 0.52% (95% CI, 0.49%-0.55%). Patients aged 5 to 11 years had the highest reported transfusion reaction rate (891.11 [95% CI, 799.81-989.11] per 100 000 products transfused). Platelet transfusions had the highest transfusion reaction rates (821.75 [95% CI, 754.14-893.80] per 100 000 products transfused), with allergic reactions being most common (506.04 [95% CI 453.30, 563.24] per 100 000 products transfused), whereas RBC transfusions had more reported febrile nonhemolytic transfusion reactions (FNHTRs; 296.20 [267.06, 327.67] per 100 000 products transfused) than other types of reactions. The most common symptoms were urticaria (69.6% [368 of 529 patients]) in allergic reactions, fever (96.5% [559 of 579 patients]) in FNHTRs, and acute respiratory distress (87.5% [21 of 24 patients]) in transfusion-associated circulatory overload (TACO); the most common treatments were antihistamines (80.3% [425 of 529 patients]) for allergic reactions, antipyretics (67.9% [393 of 579 patients]) for FNHTRs, and diuretics (83.3% [20 of 24 patients]) for TACO. Many patients (35.8% [107 of 299]) did not receive premedication after the first reaction in subsequent transfusions, regardless of reaction type. When transfusion reactions recurred, they were often of the same type (77.9% of reactions [120 of 154] after allergic reactions were allergic; 72.1% of reactions [98 of 136] after FNHTRs were FNHTRs). Conclusions and Relevance: In this cohort study of pediatric transfusion reactions, reactions appeared to be age dependent, and rates of allergic reactions and FNHTRs were higher than rates from previously published, possibly underreported, predominantly adult data. These findings underscore the importance of pediatric-specific hemovigilance to improve recognition, reporting, and safety monitoring of transfusion reactions.