Samples

We performed the study enrolling subjects during the period June-July 2020. We collected paired nasopharyngeal swabs aliquots and RNA samples extracted from the same nasopharyngeal swabs from 270 subjects collected in two phases. The first group consisted of 74 positive (n = 44) and negative (n = 30) samples. The second group of 196 samples was collected from SARS-CoV-2 positive subjects. The extracted RNA and nasopharyngeal swab sample aliquots were obtained from the National Center for Disease Control and Prevention of MH RA, National Centre for Aids Prevention of MH RA, and Davidyants Laboratories. Subject status was diagnosed at testing sites using commercially available kits (Novel Coronavirus (2019-nCoV) Nucleic Acid Diagnostic Kit, Sansure Biotech, China and SARS-CoV-2/SARS-CoV, DNA technology, Russia). Both kits contain internal control (human RNase P gene) and SARS-CoV-2/SARS-CoV additionally contains extraction control. Swab samples were stored in three different transport media types: Sample Storage Reagent (Sansure Biotech, China) (n = 45) media, PBS (n = 91) and STORE-F UTM (DNA technologies, Russia) (n = 134). No additional clinical or demographic information was collected. The study was approved by the Institutional Review Board of the Institute of Molecular Biology NAS RA (IRB#: 00004079).