The B.1.617.2 (Delta) variant of SARS-CoV-2 showed reduced sensitivity to neutralizing antibodies from recovered individuals and monoclonal antibodies. It demonstrated higher replication efficiency than B.1.1.7 and higher receptor binding and spike-mediated entry than B.1.617.1. Analysis of healthcare workers showed reduced ChAdOx vaccine effectiveness against B.1.617.2. The study concludes that the Delta variant's high fitness and immune evasion warrant continued infection control measures.

Petra Mlcochova, Steven A. Kemp, Mahesh Shankar Dhar, Guido Papa, Bo Meng, Isabella A. T. M. Ferreira, Rawlings Dati, Dana M. Collier, Anna Albeck, Sujeet Singh, Rajesh Pandey, Jonathan Brown, Jie Zhou, Niiuka Goonawardena, Swapnil Mishra, Charles Whittaker, Thomas Mellan, Robin Marwal, Meena Datt, Shantanu Sengupta, Kalaiarasuan Ponnuswamy, Venkataraman Srinivasan Radhakrishnan, Adam Abdullah, Oscar Charles, Partha Chattopadhyay, Priti Devi, Daniela Caputo, Tom Peacock, Chand Watstal, Neeraj Goel, Ambrish Satwik, Raj Vaishya, Meenakshi Agarwal, The Indian SARS-CoV-2 Genomics Consortium (INSACOG), The Complete to Phenotype Japan (G2P-Japan) Consortium, The CTIID-NIHR BioResource COVID-19 Collaboration, Antriksh Mavcousiãn, Joo Hyoen Lee, Jessica Bassi, Chiara Silacci-Fregni, Christian Saliba, Dora Pinto, Takashi Irie, Isao Yoshida, William L. Hamilton, Kei Sato, Samir Bhatt, Seth Flaxman, Leo C. James, Davide C. Lucco, Wendy S. Barclay, Partha Rakshit, Anurag Agarwal, Ravindra K. Gupta