2192. Clinical and Molecular Characteristics of Severe Respiratory Syncytial Virus Pneumonia in Critically Ill Adults

Abstract Background Respiratory syncytial virus (RSV) has been increasingly recognized as a frustrating cause of morbidity and mortality in adults. However, the clinical impact molecular characteristics severe RSV-associated pneumonia critically ill adult patients have rarely addressed. Methods This study, nested prospective cohort pneumonia, was conducted at 2,700-bed tertiary care hospital comprised two parts. In part 1, were compared with influenza (IFV)-associated between 2010 2019. 2, we performed phylogenetic amino acid analyses G protein RSV strains from three groups different infection severity 2015 2019 (Figure 1). Figure 1.Clinical samples for whole-genome sequencing 2. Results 92 RSV- 163 IFV-positive identified. Structural lung diseases, diabetes mellitus, malignancy common underlying diseases both groups. Immunocompromise (57.6% vs. 34.4%, p < 0.001) acquisition (47.8% 23.9%, significantly more group. Clinical manifestations diagnosis generally similar. The mortalities similarly high (Table 26 (group 1: 11 strains, group 2: 8 3: 7 strains) analyzed. All isolated RSV-A -B belonged to ON1 BA9 genotypes, respectively. analysis revealed that clustered by contemporary rather than other strains. There no genetic variations among groups, including subtype clades, sequence substitutions, changes potential glycosylation sites. Table 1.Characteristic outcomes 255 virus-associated Conclusion Severe commonly associated immunocompromised status. Overall features comparable IFV adults not distinct non-pneumonic or children, underscoring respiratory tract is mainly determined host factors, viral factors. Disclosures Authors: No reported disclosures.