BackgroundProven/probable lower respiratory tract infection (LRTI) caused by seasonal human coronaviruses (HCoVs) is associated with mortality after hematopoietic cell transplantation (HCT). However, risk factors for LRTI and the significance of virologic documentation of lower respiratory tract involvement by bronchoalveolar lavage (BAL) on outcome are not well characterized.MethodsPatients receiving allogeneic HCT between 4/2008 and 9/2018 with HCoV (OC43/NL63/HKU1/229E) detected in nasopharyngeal or BAL samples by PCR were retrospectively analyzed. Proven/probable LRTI was defined as having virus detected from a BAL sample with or without new pulmonary infiltrates by chest radiography, respectively. Possible LRTI was defined as having virus detected from an upper respiratory tract sample with new pulmonary infiltrates. We used logistic regression models to evaluate risk factors for LRTI in patients with first documented HCoV infection during pretransplant conditioning or post-HCT. Overall mortality following proven/probable and possible LRTI was compared by the log-rank test.ResultsA total of 297 patients (61 children and 236 adults) developed HCoV infection as follows: 254 had upper respiratory tract infection (URTI) alone, 18 presented with LRTI, and 25 progressed from URTI to LRTI [median 16 days (range, 2–62 days)]. Multivariable analyses showed that male gender, higher immunodeficiency scoring index, albumin < 3 g/dl, glucose > 150 mg/dl and presence of respiratory copathogen at HCoV diagnosis were associated with the occurrence of LRTI (Figure 1). Patients with proven/probable LRTI (N=16) had significantly worse survival than those with possible LRTI (N=37) (p=0.006, Figure 2).Figure 1. Figure 2. ConclusionOur analyses identified risk factors (hypoalbuminemia, male gender, high glucose and presence of respiratory copathogen) uncommonly appreciated for LRTI due to other respiratory viruses in HCT recipients. Whether these factors are also relevant to LRTI due to SARS-CoV-2 after HCT requires further studies. The association of hyperglycemia with LRTI might provide an opportunity to reduce the risk of LRTI.Disclosures Alpana Waghmare, MD, Amazon (Grant/Research Support)Amazon (Employee, Shareholder)Ansun Biopharma (Scientific Research Study Investigator)Kyorin Pharmaceuticals (Advisor or Review Panel member) Janet A. Englund, MD, AstraZeneca (Scientific Research Study Investigator)GSK group of companies (Scientific Research Study Investigator)Meissa vaccines (Consultant)Merck (Scientific Research Study Investigator)Sanofi Pasteur (Consultant) Michael Boeckh, MD PhD, AlloVir (Consultant)EvrysBio (Advisor or Review Panel member, Other Financial or Material Support, share options)Gilead (Consultant, Grant/Research Support)GSK (Consultant)Helocyte (Advisor or Review Panel member, Shareholder)Lophius (Grant/Research Support)Merck (Consultant, Grant/Research Support)SymBio (Consultant)VirBio (Consultant, Grant/Research Support)