The effect of vaccination on severity of subsequent COVID‐19 in patients with hematologic malignancies (HM) is unknown. In this single‐center retrospective cohort study, we found no difference in severity of COVID‐19 disease in vaccinated (n = 16) versus unvaccinated (n = 54) HM patients using an adjusted multiple logistic regression model. Recent anti‐B‐cell therapy was associated with more severe illness. This article is protected by copyright. All rights reserved

Background Pneumonia is the most common infectious cause of morbidity and excess mortality complicating hematopoietic cell transplantation (HCT) and treatment of hematologic malignancy. Standard bronchoscopic and noninvasive microbiologic testing identify causative pathogens in less than half of cases. The Karius Test, a plasma next-generation sequencing assay of microbial cell-free DNA, may improve diagnostic yield in these patients. Methods Patients with active hematologic malignancy or recent HCT undergoing bronchoscopy for suspected pneumonia were prospectively enrolled in this observational study conducted at 10 United States medical centers. A panel of expert clinicians blinded to Karius Test results reviewed a standardized panel of microbiologic and molecular testing from bronchoalveolar lavage and blood samples for bacterial and fungal testing, nasopharyngeal swab for respiratory viral testing, imaging results, clinical documentation, and any additional microbiologic or molecular testing collected per usual standard of care to adjudicate a probable cause of pneumonia. The panel then adjudicated whether a probable cause of pneumonia or other clinically relevant infection was identified by the Karius Test. Results Between January 3, 2020 and February 4, 2022, 257 patients were enrolled. A planned interim analysis of the first 69 sequentially enrolled patients in the per protocol population was conducted. An adjudicated probable cause of pneumonia was identified by standard care in 18/69 (26%) patients. The Karius Test identified an adjudicated probable cause of pneumonia in 10/51 (20%) patients when no cause of pneumonia was identified by standard care testing. The combination of standard care and the Karius Test together identified a probable cause of pneumonia in 28/69 (41%) patients. At least one additional pathogen adjudicated as a probable cause of pneumonia was identified by the Karius Test in 6/18 (33%) of patients with positive standard care testing. Conclusion The Karius Test notably increased the probability of identifying a pathogenic cause of pneumonia among immunocompromised patients undergoing bronchoscopy. The additive diagnostic value of the Karius Test may significantly enhance management of this common condition. Disclosures Roy F. Chemaly, MD/MPH, Karius: Advisor/Consultant|Karius: Grant/Research Support Radha Duttagupta, PhD, Karius Inc: Stocks/Bonds Sanjeet S. Dadwal, MD, FACP, FIDSA, AlloVir: Advisor/Consultant|AlloVir: Grant/Research Support|Ansun Biopharma: Grant/Research Support|Aseptiscope: Advisor/Consultant|Aseptiscope: Stocks/Bonds|Astellas: Speaker's Bureau|Cidara: Advisor/Consultant|Gilead: Grant/Research Support|Karius: Grant/Research Support|Merck: Advisor/Consultant|Merck: Grant/Research Support|Merck: Speaker's Bureau|Takeda: Speaker's Bureau Joshua A. Hill, MD, Allovir: Advisor/Consultant|Allovir: Grant/Research Support|Covance/CSL: Advisor/Consultant|CRISPR: Advisor/Consultant|Deverra: Grant/Research Support|Gilead: Grant/Research Support|Karius: Advisor/Consultant|Karius: Grant/Research Support|Merck: Grant/Research Support|Octapharma: Advisor/Consultant|OptumHealth: Advisor/Consultant|Oxford Immunotec: Grant/Research Support|Pfizer: Advisor/Consultant|Symbio: Advisor/Consultant|Takeda: Advisor/Consultant Ghady Haidar, MD, Karius, Allovir, and AstraZeneca: Grant/Research Support Alfred Luk, MD, Karius: Grant/Research Support Jamie Todd, MD, Altavant Sciences: Advisor/Consultant|AstraZeneca: Grant/Research Support|Boehringer Ingelheim: Grant/Research Support|CareDx: Grant/Research Support|Cellarity: Advisor/Consultant|Natera: Advisor/Consultant Genovefa Papanicolaou, MD, AlloVir: Board Member|AlloVir: Serve as member of DSMC|Amplyx: Board Member|Amplyx: Serve as member of DSMC|Astellas: Advisor/Consultant|Cidara: Advisor/Consultant|CSL Behring: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Merck: Investigator for Merck|MSD: Advisor/Consultant|Octapharma: Advisor/Consultant|Octapharma: Board Member|Octapharma: Serve as EAC member|Partners RX: Advisor/Consultant|SymBio: Advisor/Consultant|Takeda: Advisor/Consultant|Takeda: Grant/Research Support|Takeda: Investigator for Takeda|Vera: Board Member|Vera: Serve as member of DSMC Elena Nemirovich-Danchenko, MD PhD, Karius: Stocks/Bonds Mona Mughar, BS, Karius: Stocks/Bonds Sudeb Dalai, MD, Karius: Stocks/Bonds Sudeb Dalai, MD, Karius: Stocks/Bonds Yuen Cho, MS, CLS(CA-DPH), Karius: Stocks/Bonds Asim A. Ahmed, MD, Karius: Employee|Karius: Stocks/Bonds Desiree Hollemon, MSN, MPH, Karius: Stocks/Bonds David K. Hong, MD, Janssen Pharmaceutical Companies of Johnson & Johnson: Employee|Vir Biotechnology: Employee|Vir Biotechnology: Stocks/Bonds Marla Lay Vaughn, BS, MT(ASCP), Karius: Employee|Karius: Stocks/Bonds Tim Blauwkamp, PhD, Karius: Board Member|Karius: Ownership Interest Zivjena Vucetic, MD, Karius: Stocks/Bonds Rina Romano, BS, Karius Inc: Stocks/Bonds|Karius Inc: Stocks/Bonds Rina Romano, BS, Karius Inc: Stocks/Bonds|Karius Inc: Stocks/Bonds Rina Romano, BS, Karius Inc: Stocks/Bonds|Karius Inc: Stocks/Bonds Vance G. Fowler, Jr, MD, MHS, Affinergy: Grant/Research Support|Affinergy: Honoraria|Affinium: Honoraria|Amphliphi Biosciences: Honoraria|ArcBio: Stocks/Bonds|Basilea: Grant/Research Support|Basilea: Honoraria|Bayer: Honoraria|C3J: Honoraria|Cerexa/Forest/Actavis/Allergan: Grant/Research Support|Contrafect: Grant/Research Support|Contrafect: Honoraria|Cubist/Merck: Grant/Research Support|Debiopharm: Grant/Research Support|Deep Blue: Grant/Research Support|Destiny: Honoraria|Genentech: Grant/Research Support|Genentech: Honoraria|Integrated Biotherapeutics: Honoraria|Janssen: Grant/Research Support|Janssen: Honoraria|Karius: Grant/Research Support|Medicines Co.: Honoraria|MedImmune: Grant/Research Support|MedImmune: Honoraria|NIH: Grant/Research Support|Novartis: Grant/Research Support|Novartis: Honoraria|Pfizer: Grant/Research Support|Regeneron: Grant/Research Support|Regeneron: Honoraria|Sepsis diagnostics: Sepsis diagnostics patent pending|UpToDate: Royalties|Valanbio: Stocks/Bonds Thomas L. Holland, MD, Aridis: Advisor/Consultant|Lysovant: Advisor/Consultant.

Background: Fever is a common complication in hematopoietic stem-cell transplant recipients, yet an etiology is often not found. Plasma microbial cell-free DNA sequencing may improve diagnosis and management of fever in this population. Methods: This prospective study (ClinicalTrials.gov;NCT02804464) enrolled 70 patients undergoing allogeneic HCT and followed them for one year. Plasma microbial cell-free DNA sequencing was collected within 24 hours of fever and for infection surveillance weekly after HCT through day 63 post-HCT followed by monthly until study end. Plasma mcfDNA sequencing results were compared with all standard microbiological testing results collected within 48 hours of fever onset. Results: Among 53 fevers eligible for analysis, clinical adjudication determined that a probable cause of fever was detected by blood culture in in 7 (13%), by all microbiology in 9 (17%), and by plasma microbial cell-free DNA sequencing in 12 (23%), including 5 in which microbiology was negative, increasing the diagnostic yield by 56%. The positive percent agreement with microbiology was 78% (7/9) and the negative percent agreement was 89% (39/44). Adjudication determined that plasma microbial cell-free DNA sequencing results would have led to a change in antimicrobial management in 55% (7/12) of fevers with detections. Weekly surveillance with plasma microbial cell-free DNA sequencing detected 8 of 15 causative pathogens prior to fever by a mean of 4.8 days (range 1-8 days). Conclusions: Plasma microbial cell-free DNA sequencing shows promise in the surveillance, diagnosis and management of fever in hematopoietic stem cell transplant recipients.