Disparate kinetics of viable virus shedding in immunocompromised patients: SARS-CoV-2 versus influenza virus – a prospective real-world cohort study

There are limited data comparing viral shedding between influenza and SARS-CoV-2 in immunocompromised patients. We prospectively enrolled 70 SARS-CoV-2 and 16 influenza patients, with 48 SARS-CoV-2 patients matched to 16 influenza patients by propensity score. Weekly-collected respiratory samples were subjected to viral culture and antigen testing. In matched cohorts, the time to culture-confirmed viral clearance was shorter for influenza than SARS-CoV-2 (median, 4.5 vs. 29 days; adjusted Hazard Ratio [aHR] 27.5; P <0.001), and antigen negativity occurred faster (3 vs. 23 days; aHR 19.2; P <0.001). These findings show different clearance kinetics for influenza and SARS-CoV-2 in immunocompromised patients.