Genomic Characterization of an Emerging SARS-CoV-2 Variant During the Early Second Wave of the SARS-CoV-2 Pandemic in Maharashtra, India.

Background The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has led to a global health crisis, with various variants emerging over time. In India, particularly in Maharashtra, a resurgence of cases and distinct transmission patterns have been observed. This study aimed to identify and characterize the circulating SARS-CoV-2 variants during the early second wave in Maharashtra, India. Materials and methods Nasopharyngeal swabs were collected from 24 RT-PCR-positive coronavirus disease of 2019 (COVID-19) cases across four districts of Maharashtra. Whole genome sequencing (WGS) was performed using the ARTIC amplicon sequencing protocol, and the data were analyzed. Results A total of 189 amino-acid mutations were identified across the 24 samples. Compared to the Indian genomes, 44 amino-acid mutations were unique to 24 genomes. Clade 20A was the most prevalent (66.66%), followed by 20B and 21B. The lineage B.1.36 (45.83%) was the most common, followed by B.1.617.1 (16.67%). The D614G mutation was the most frequent spike mutation (95.83%). Four samples from the Amravati district clustered distinctly under Clade 21B with spike mutations E154K in the N-terminal domain (NTD), L452R and E484Q in the receptor-binding domain (RBD) and P681R in proximity to the furin cleavage site. The temporal distribution of samples revealed the presence of Clade 21B in Maharashtra since the 31st of January 2021. Conclusion The study provides valuable insights into the circulating SARS-CoV-2 variants during the early second wave in Maharashtra, highlighting specific clades and mutations. The unique clustering patterns and the high prevalence of immune-escape mutations emphasize the need for continuous monitoring and genomic surveillance.