The SARS-CoV-2 Delta (B.1.617.2) variant with spike N501Y mutation in the shadow of Omicron emergence

Circulation of the Omicron variant with the reemergence of the N501Y mutation along with many others in the spike protein has once again stirred the academic community. Interestingly, tracing the genetic diversity of SARS-CoV-2 shed light on a less frequent N501Y + Delta variant which has been in the global circulation for some time before the Omicron appearance. This paper aims to present the molecular characteristics of the SARS-CoV-2 Spike_N501Y + Delta variant detected in Bosnia and Herzegovina. The study was conducted during November and December 2021. All patients were tested using real-time RT-PCR for detection of SARS-CoV-2. A representative number of SARS-CoV-2 positive samples was pre-screened using VirSNiP SARS-CoV-2 Spike N501Y kit. The characterization of the viruses was carried out with Illumina RNA Prep with enrichment and the Respiratory Virus Oligo Panel kit. Among the analyzed sequences, we found two isolates of the Delta variant that differ from their most related clade- GK AY.4.3 in additional mutations N501Y and L54F. In this study, we described the presence of a rare form of Delta variant with Spike_N501Y mutation in the shadow of the Omicron emergence. Despite the set of mutations in the Spike protein, this form of Delta variant does not indicate the large-scale consequences for the general population. Further functional studies of this form could provide more information about its antigenicity and infectivity.