Screening for Imported Infections in Pediatric Patients Prior to Immunosuppressive Therapy

: Purpose To describe the prevalence of imported infections in pediatric patients prior to immunosuppressive therapy after implementing a structured screening protocol, and to assess adherence and diagnostic yield. Methods Retrospective study of patients <18 years from non-Western countries screened between 2020-2024 at a tertiary hospital in Madrid, Spain. Screening followed a standardized protocol including serology, tuberculosis testing, stool analysis, and vaccination assessment. Results Sixty-three children were included (median age 9.5 years; 55.6% male), mainly from Latin America (65.1%), with hematologic malignancies (52.4%) or awaiting solid organ transplant (33.3%). Only 19% completed full screening. At least one infection was detected in 28.6%, mainly toxoplasmosis (7/57, 12.3%), strongyloidiasis (5/56, 8.9%), malaria (3/22, 13.6%), and schistosomiasis (3/25, 12%). Immunity to hepatitis B (65.5%), measles and varicella (<50%) was suboptimal. Conclusion Imported infections were frequent, supporting systematic screening before immunosuppression.