Low SARS-CoV-2 viral load among vaccinated individuals infected with Delta B.1.617.2 and Omicron BA.1.1.529 but not with Omicron BA.1.1 and BA.2 variants

The rapid spread of SARS-CoV-2 variants in the global population is indicative of the development of selective advantages in emerging virus strains. Here, we performed a case-control investigation of the clinical and demographic characteristics, clinical history, and virological markers to predict disease progression in hospitalized adults for COVID-19 between December 2021 and January 2022 in Chennai, India. COVID-19 diagnosis was made by a commercial TaqPath COVID-19 RT-PCR, and WGS was performed with the Ion Torrent Next Generation Sequencing System. High-quality (Funding Agencies|Xiamen University Malaysia Research Funding (XMUMRF) [XMUMRF/2018-C2/ILAB/0001, XMUMRF/2020-C5/ITCM/0003, XMUMRF/2018-C1/IENG/0005]; Swedish Research Council; Swedish, Physicians against AIDS Research Foundation; Swedish International Development Cooperation Agency; SIDA SARC; VINNMER for Vinnova; Swedish Society of Medicine [AI52731]; Department of Science and Technology-Science and Engineering Research Board, Government of India [CRG/2019/006096]; CALF; Linkoeping University Hospital Research Fund