Utilization of a SARS-CoV-2 Variant Assay for the Rapid Differentiation of Omicron and Delta

The emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant (B.1.1.529), creates a diagnostic vacuum, since differentiation of Omicron from Delta relies on relatively slow next generation sequencing (NGS) technology delaying epidemiologic understanding and therapeutic intervention. The RUO SARS-CoV-2 Variant Set 1 Test (RSCov2V1) RT-PCR for detection of spike gene N501Y, E484K and del69-70 was designed to differentiate Alpha from Beta and Gamma variants. While Delta lacks these three variants, Omicron has the N501Y and del69-70 mutation. We submitted 88 samples for RSCov2V1 identifying 9 samples with the N501Y and del69-70 mutations while all other samples (79) were negative for all three variants. 9/9 samples with the del69-70 and N501Y were identified by NGS to be Omicron while 47/47 other samples assessed by NGS were confirmed to be Delta family variants. We demonstrate here that an immediately available RT-PCR assay for detection of spike gene N501Y and del69-70 can be utilized to rapidly differentiate Omicron from Delta variants in the proper epidemiologic context