Genomic evidence of co-identification with Omicron and Delta SARS-CoV-2 variants: a report of two cases.

On November 24, 2021, a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant assigned to the lineage B.1.1.529 (Omicron) was first reported to the World Health Organization from South Africa. Despite the co-circulation of several SARS-CoV-2 variants, co-infection by different variants is not commonly identified. Here, we report two cases of SARS-CoV-2 co-identifications with the Omicron and Delta variants.