Abstract
BACKGROUND: Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract illnesses (LRI) worldwide, particularly affecting high-risk groups such as cancer patients, solid organ transplant (SOT) recipients, older adults, and those with significant comorbidities. The Advisory Committee on Immunization Practices (ACIP) recommends vaccinating adults aged ≥75 years, and those aged 60-74 at greater risk for severe RSV disease (1). Recently, they proposed expanding this recommendation to at-risk patients aged 50-59 (2). Our study aims to investigate outcomes of RSV infection and identify risk factors for complications in various populations. [Figure: see text] [Figure: see text] METHODS: We conducted an international multicenter retrospective observational study including adults with RSV infection across six centers in the USA, the Netherlands, Israel, and Taiwan from October 2018 to April 2024. Patients were categorized based on underlying conditions: cancer, SOT recipients, and those without either. Primary outcomes included LRI and 30-day all-cause and RSV-related mortality. [Figure: see text] [Figure: see text] RESULTS: We analyzed 562 patients: 425 (75.6%) with cancer, mainly hematologic malignancies (HMs), and 53 (9.4%) SOT recipients (Table 1). Most patients without either cancer or SOT (84 patients, 15.0%) had significant comorbidities, with 73.8% having a Charlson comorbidity index (CCI) ≥4. Overall LRI rates were 46.8% (48.9% in cancer patients, 35.8% in SOT recipients, and 42.9% in others), with 30-day mortality of 8.0% (7.3% in cancer patients, 11.3% in SOT recipients, and 9.5% in others). LRI and mortality by age group and underlying condition are presented in Figure 1. Independent risk factors for LRI were older age, higher CCI, HMs, smoking, recent steroid use, lymphopenia, and elevated creatinine levels, but the type of underlying condition was not independently associated with LRI (Table 2a). Independent risk factors for 30-day mortality were SOT (compared to cancer), metastatic solid malignancy, nosocomial infection, neutropenia, respiratory co-infection, and LRI (Table 2b, Figure 2). CONCLUSION: The study highlights significant morbidity and mortality from RSV in patients with cancer and SOT recipients, as well as in patients without these conditions who are over 50 years of age. DISCLOSURES: Jonathan Hand, MD, AstraZeneca: Advisor/Consultant|AstraZeneca: Grant/Research Support|Ferring: Grant/Research Support|Innoviva: Advisor/Consultant|Janssen: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|Scynexis: Grant/Research Support|The Antibiotic Resistance Leadership Group (ARLG): Grant/Research Support|The Antibiotic Resistance Leadership Group (ARLG): Honoraria Lior Nesher, MD, AstraZeneca: Advisor/Consultant|AstraZeneca: Honoraria|F2G: Grant/Research Support|GSK: Advisor/Consultant|GSK: Honoraria|Medison: Advisor/Consultant|Moderna: Honoraria|MSD: Advisor/Consultant|MSD: Honoraria|Pfizer: Grant/Research Support|Pfizer: Honoraria|Takeda: Honoraria Roy F. Chemaly, MD, MPH, FIDSA, FACP, FESCMID, ADMA Biologics: Advisor/Consultant|AiCuris: Advisor/Consultant|AiCuris: Grant/Research Support|Ansun Biopharma: Advisor/Consultant|Ansun Biopharma: Grant/Research Support|Assembly Bio: Advisor/Consultant|Astellas: Advisor/Consultant|Eurofins Viracor: Advisor/Consultant|Eurofins Viracor: Grant/Research Support|Genentech: Grant/Research Support|Gilead: Advisor/Consultant|InflaRX: Advisor/Consultant|IntegerBio: Advisor/Consultant|Karius: Advisor/Consultant|Karius: Grant/Research Support|Merck/MSD: Advisor/Consultant|Merck/MSD: Grant/Research Support|Moderna: Advisor/Consultant|Oxford Immunotec: Advisor/Consultant|Pfizer: Advisor/Consultant|Shionogi: Advisor/Consultant|Takeda: Advisor/Consultant|Takeda: Grant/Research Support|Tether: Advisor/Consultant