Genomic surveillance of SARS-CoV-2 reveals emergence of Omicron BA.2 in Islamabad, Pakistan

The Omicron variant of SARS-CoV-2 has rapidly replace previous variants of SARS CoV2 around the globe and is now a major variant of concern. The genomic surveillance of Omicron variant also reveals spread of its subvariant BA.2 which has differing transmissibility in comparison to its other subvariant BA.1. BA.1 and BA.2 harbors different mutational profile. One of the important change in both the subvariants is the presence of 69-70 deletion in BA.1 and absence of this deletion in BA.2. This deletion can be used as tool for the detection of omicron sub variants using real time PCR. In the current study we have used the TaqPath COVID-19 PCR kit for the detection of 69-70 deletion followed by genotyping using SNPsig® SARS-CoV-2 (EscapePLEX) kit (PrimerDesign, UK) that target K417N, E484K, and P681R mutations. The samples with the amplification of spike gene and K417N were termed as probable BA.2 cases. A subset of samples (n=13) were further subjected to whole genome sequencing. The results showed all the 13 samples were of BA.2. Hence, this assay can be used as a cost effective method for the detection of omicron BA.2 variant using real time PCR in resource limiting settings. Moreover, the detection of BA.2 with highly transmissible mutations in Islamabad, Pakistan may potentially increase the number of positive cases. In that scenario, there has to be stringent genomic surveillance to understand the circulating lineages in the country.