We used residual NP samples remaining after clinical testing for CXCL10 measurements and transcriptome analysis. Swab-associated viral transport medium was stored at −80°C following clinical testing and thawed just before ELISA assay or RNA isolation for RNA-seq. Clinical information, including age, sex, virology results, and specific features of clinical course (including presenting symptoms, hospital admission, and length of stay), was extracted from the electronic medical record and recorded, after which samples were assigned a study code and deidentified. In the clinical laboratory, SARS-CoV-2 was detected in most samples using an Emergency Use Authorization–approved TaqMan assay detecting the CDC targets N1, N2, and RNaseP (Centers for Disease Control and Prevention, 2020 ). In some longitudinal samples, SARS-CoV-2 was diagnosed with the commercial Cepheid assay (Cepheid, 2021 ); in this case, RT-qPCR for the CDC N1 gene was repeated using RT-qPCR TaqMan assay for the CDC N1 gene as described previously (catalog no. 10006600; Integrated DNA Technologies; Vogels et al., 2020 (link)).