ABSTRACT
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.
ABSTRACT
BACKGROUND: The SARS-CoV-2 Omicron variants BA.2.74, BA.2.75, and BA.2.76 have appeared recently in India and have already spread to over 40 countries. They have acquired additional mutations in their spike protein compared to BA.2, branching away on the SARS-CoV-2 phylogenetic tree. These added mutations have raised concerns about the impact on viral pathogenicity, transmissibility, and immune evasion properties of the new variants. MATERIAL AND METHODS: A total of 990 Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) positive SARS-CoV-2 samples, with a cycle threshold value (Ct) less than 25, were processed for SARS-CoV-2 whole genome sequencing between June 3, 2022 to August 7, 2022. All corresponding demographic and clinical data were recorded and analyzed using Microsoft® Excel. RESULTS: Out of 990 samples sequenced, BA.2.75 (23.03%) was the predominant Omicron sublineage, followed by BA.2.38 (21.01%), BA.5 (9.70%), BA.2 (9.09%), BA.2.74 (8.89%) and BA.2.76 (5.56%). A total of 228 cases of BA.2.74, BA.2.75, and BA.2.76 were contacted by telephone, of which 215 (94.30%) were symptomatic with mild symptoms, and 13 (5.70%) had no symptoms. Fever (82.02%) was the most common symptom, followed by cough (49.12%), cold (35.97%), fatigue (27.19%), headache (21.05%), and myalgia (20.61%). Of the 228 cases, 195 (85.53%) cases recovered at home, and 33 (14.47%) required institutional quarantine. Recovery with conservative treatment was observed in 92.98% of cases, while 4.83% required additional oxygen therapy. Only three (1.32%) cases had poor outcomes resulting in death, and the remaining 225 (98.68%) survived. Among the 228 cases, 219 (96.05%) cases were vaccinated with the COVID-19 vaccine; of these, 72.60% had received both doses, 26.03% had also received the precautionary booster dose, while 1.37% were incompletely vaccinated with a single dose of vaccine. CONCLUSION: The current study indicates that the three BA.2 sublineages are causing mild disease in India. However, BA.2.75 has key mutations that are notable for accelerated growth and transmission and require close and effective monitoring.
