Definition: In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
Input: Background. Recent data suggest that human coronavirus (HCoV) pneumonia is associated with significant mortality in hematopoietic cell transplant (HCT) recipients. Investigation of risk factors for prolonged shedding and intrahost genome evolution may provide critical information for development of novel therapeutics. Methods. We retrospectively reviewed HCT recipients with HCoV detected in nasal samples by polymerase chain reaction (PCR). HCoV strains were identified using strain-specific PCR. Shedding duration was defined as time between first positive and first negative sample. Logistic regression analyses were performed to evaluate factors for prolonged shedding (≥21 days). Metagenomic next-generation sequencing (mNGS) was conducted when ≥4 samples with cycle threshold values of <28 were available. Results. Seventeen of 44 patients had prolonged shedding. Among 31 available samples, 35% were OC43, 32% were NL63, 19% were HKU1, and 13% were 229E; median shedding duration was similar between strains (P = .79). Bivariable logistic regression analyses suggested that high viral load, receipt of high-dose steroids, and myeloablative conditioning were associated with prolonged shedding. mNGS among 5 subjects showed single-nucleotide polymorphisms from OC43 and NL63 starting 1 month following onset of shedding. Conclusions. High viral load, high-dose steroids, and myeloablative conditioning were associated with prolonged shedding of HCoV in HCT recipients. Genome changes were consistent with the expected molecular clock of HCoV.

Prolonged Shedding of Human Coronavirus in Hematopoietic Cell Transplant Recipients: Risk Factors and Viral Genome Evolution