Methods

Study design and setting

This retrospective case series evaluated adult stem cell transplant recipients who received combination therapy with palivizumab and ribavirin for respiratory syncytial virus (RSV) infection during the early peri-transplantation period. Cases were identified from the tertiary transplant center, King Abdulaziz Medical City, Riyadh, Saudi Arabia, between January 2023 to June 2026.

Patient selection and data collection

Eligible patients included adults (≥18 years) who underwent allogeneic or autologous hematopoietic stem cell transplantation and developed laboratory-confirmed RSV infection between 1 week prior to cell infusion and engraftment. Patients who received combination palivizumab and ribavirin therapy were included. Patients were excluded if they had incomplete medical records or if RSV infection occurred outside the defined peri-transplantation period. Extracted data included patient and transplant characteristics, immunosuppression, laboratory and RSV infection parameters, treatments, adverse events, clinical outcomes, and 30- and 90-day mortality.

RSV diagnosis and classification

RSV infection was confirmed by reverse transcription polymerase chain reaction (RT-PCR) from nasopharyngeal swab or bronchoalveolar lavage. Infections were classified as upper respiratory tract infection (URTI) or lower respiratory tract infection (LRTI) based on clinical and radiographic findings. LRTI was defined as the presence of new pulmonary infiltrates on chest imaging with respiratory symptoms and/or hypoxemia.

Risk stratification

Patients were stratified by the immunodeficiency severity index that was validated to predict poor outcomes in hemoatopoietic cell transplant [10]. It consists of 7 elements with each with assigned weights between 1 and 3 points. High-risk features included absolute neutrophil counts < 500 cells/μL (3 points), lymphocyte count < 200 cells/μL (3 points), age > = 40 years (2 points), myeloablative conditioning regimen (1 point), graft versus host diseases (GVHD) (1 point), corticosteroid (1 point), and recent or pre-engraftment allo-SCT (1 point).

Treatment protocol

Ribavirin Administration: Ribavirin was administered orally at a dose of 10–30 mg/kg body weight in three divided doses, maximum 600 mg every 8 h, total daily dose up to 1800 mg. Treatment duration was determined by clinical response and ranged from 7 to 21 days.

Palivizumab Administration: Palivizumab was administered at a dose of 15 mg/kg via intramuscular injection or intravenous route, at single or repeated doses. The actual received dose is written in the case section.

Adjunctive Therapy: Intravenous immunoglobulin (IVIG) was administered at 0.5 g/kg bodyweight for patients with hypogammaglobulinemia or at high risk for progression to LRTI. Up to five doses were prescribed according to the discretion of the treating physician. Supportive care included bronchodilators, supplemental oxygen, intravenous fluids, and antipyretics as clinically indicated.

Outcome measures and safety monitoring

Primary outcomes included clinical response (resolution of respiratory symptoms and radiographic findings) and all-cause mortality at 30 and 90 days. Secondary outcomes included viral clearance and adverse events related to therapy. Ribavirin-related toxicities and drug interactions were monitored daily during hospitalization and at outpatient follow-up, with dose adjustment or discontinuation based on toxicity severity. Follow up for survived patients was extended until the last day of the study.