Surveillance of omicron variant in Kangra District of Himachal Pradesh, India during the 3rd disease wave of COVID-19.

Abstract

The coronavirus disease 2019 (COVID-19) wave has fluctuated erratically around the globe over the past three years of the pandemic, sometimes declining and at other times surging. The cases of infection in India have remained low, despite the continued surge of Omicron sub-lineages reported in a few countries. In this study, we determined the presence of the circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains in the population of Kangra District, Himachal Pradesh, India. In vitro diagnostic real-time reverse transcriptase polymerase chain reaction (RT-qPCR) was performed using Tata MD CHECK RT-PCR Omisure kit (Tata Medical and Diagnostics Limited, Maharashtra, India), to detect the presence of Omicron in target samples. A total of 400 samples were analyzed in this study; 200 each for the second and third waves, respectively. The S gene target failure (SG-TF) and S gene mutation amplification (SG-MA) primer-probe sets were used. Our results corroborated that during the third wave, SG-MA amplification was noted, while amplification of SG-TF was not, and vice versa in the case of the second wave, indicating that all the tested patients were infected with the Omicron variant during the third wave, while Omicron was absent during the second wave. This study added more information about the prevalence of Omicron variants during the third wave in the chosen area, and it projected a use of in vitro RT-qPCR method for rapid prospective determination of the prevalence of the variant of concern (VOC) in developing countries with limited sequencing facility.