@article {2323,
	title = {Genomic characterization and epidemiology of an emerging SARS-CoV-2 variant in Delhi, India.},
	journal = {Science},
	year = {2021},
	month = {2021 Oct 14},
	pages = {eabj9932},
	abstract = {<p>Delhi, the national capital of India, has experienced multiple SARS-CoV-2 outbreaks in 2020 and reached population seropositivity of over 50\% by 2021. During April 2021, the city became overwhelmed by COVID-19 cases and fatalities, as a new variant B.1.617.2 (Delta) replaced B.1.1.7 (Alpha). A Bayesian model explains the growth advantage of Delta through a combination of increased transmissibility and reduced sensitivity to immune responses generated against earlier variants (median estimates; {\texttimes}1.5-fold, 20\% reduction). Seropositivity of an employee and family cohort increased from 42\% to 87.5\% between March and July 2021, with 27\% reinfections, as judged by increased antibody concentration after a previous decline. The likely high transmissibility and partial evasion of immunity by the Delta variant contributed to an overwhelming surge in Delhi.</p>
},
	issn = {1095-9203},
	doi = {10.1126/science.abj9932},
	author = {Dhar, Mahesh S and Marwal, Robin and Vs, Radhakrishnan and Ponnusamy, Kalaiarasan and Jolly, Bani and Bhoyar, Rahul C and Sardana, Viren and Naushin, Salwa and Rophina, Mercy and Mellan, Thomas A and Mishra, Swapnil and Whittaker, Charles and Fatihi, Saman and Datta, Meena and Singh, Priyanka and Sharma, Uma and Ujjainiya, Rajat and Bhatheja, Nitin and Divakar, Mohit Kumar and Singh, Manoj K and Imran, Mohamed and Senthivel, Vigneshwar and Maurya, Ranjeet and Jha, Neha and Mehta, Priyanka and A, Vivekanand and Sharma, Pooja and Vr, Arvinden and Chaudhary, Urmila and Soni, Namita and Thukral, Lipi and Flaxman, Seth and Bhatt, Samir and Pandey, Rajesh and Dash, Debasis and Faruq, Mohammed and Lall, Hemlata and Gogia, Hema and Madan, Preeti and Kulkarni, Sanket and Chauhan, Himanshu and Sengupta, Shantanu and Kabra, Sandhya and Gupta, Ravindra K and Singh, Sujeet K and Agrawal, Anurag and Rakshit, Partha and Nandicoori, Vinay and Tallapaka, Karthik Bharadwaj and Sowpati, Divya Tej and Thangaraj, K and Bashyam, Murali Dharan and Dalal, Ashwin and Sivasubbu, Sridhar and Scaria, Vinod and Parida, Ajay and Raghav, Sunil K and Prasad, Punit and Sarin, Apurva and Mayor, Satyajit and Ramakrishnan, Uma and Palakodeti, Dasaradhi and Seshasayee, Aswin Sai Narain and Bhat, Manoj and Shouche, Yogesh and Pillai, Ajay and Dikid, Tanzin and Das, Saumitra and Maitra, Arindam and Chinnaswamy, Sreedhar and Biswas, Nidhan Kumar and Desai, Anita Sudhir and Pattabiraman, Chitra and Manjunatha, M V and Mani, Reeta S and Arunachal Udupi, Gautam and Abraham, Priya and Atul, Potdar Varsha and Cherian, Sarah S}
}
@article {2363,
	title = {SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion.},
	journal = {Nature},
	volume = {599},
	year = {2021},
	month = {2021 11},
	pages = {114-119},
	abstract = {<p>The B.1.617.2 (Delta) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha). In vitro, B.1.617.2 is sixfold less sensitive to serum neutralizing antibodies from recovered individuals, and eightfold less sensitive to vaccine-elicited antibodies, compared with wild-type Wuhan-1 bearing D614G. Serum neutralizing titres against B.1.617.2 were lower in ChAdOx1 vaccinees than in BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies to the receptor-binding domain and the amino-terminal domain. B.1.617.2 demonstrated higher replication efficiency than B.1.1.7 in both airway organoid and human airway epithelial systems, associated with B.1.617.2 spike being in a predominantly cleaved state compared with B.1.1.7 spike. The B.1.617.2 spike protein was able to mediate highly efficient syncytium formation that was less sensitive to inhibition by neutralizing antibody, compared with that of wild-type spike. We also observed that B.1.617.2 had higher replication and spike-mediated entry than B.1.617.1, potentially explaining the B.1.617.2 dominance. In an analysis of more than 130 SARS-CoV-2-infected health care workers across three centres in India during a period of mixed lineage circulation, we observed reduced ChAdOx1 vaccine effectiveness against B.1.617.2 relative to non-B.1.617.2, with the caveat of possible residual confounding. Compromised vaccine efficacy against the highly fit and immune-evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era.</p>
},
	keywords = {Antibodies, Neutralizing, Cell Fusion, Cell Line, COVID-19 Vaccines, Female, Health Personnel, Humans, Immune Evasion, India, Kinetics, Male, SARS-CoV-2, Spike Glycoprotein, Coronavirus, Vaccination, Virus Replication},
	issn = {1476-4687},
	doi = {10.1038/s41586-021-03944-y},
	author = {Mlcochova, Petra and Kemp, Steven A and Dhar, Mahesh Shanker and Papa, Guido and Meng, Bo and Ferreira, Isabella A T M and Datir, Rawlings and Collier, Dami A and Albecka, Anna and Singh, Sujeet and Pandey, Rajesh and Brown, Jonathan and Zhou, Jie and Goonawardane, Niluka and Mishra, Swapnil and Whittaker, Charles and Mellan, Thomas and Marwal, Robin and Datta, Meena and Sengupta, Shantanu and Ponnusamy, Kalaiarasan and Radhakrishnan, Venkatraman Srinivasan and Abdullahi, Adam and Charles, Oscar and Chattopadhyay, Partha and Devi, Priti and Caputo, Daniela and Peacock, Tom and Wattal, Chand and Goel, Neeraj and Satwik, Ambrish and Vaishya, Raju and Agarwal, Meenakshi and Mavousian, Antranik and Lee, Joo Hyeon and Bassi, Jessica and Silacci-Fegni, Chiara and Saliba, Christian and Pinto, Dora and Irie, Takashi and Yoshida, Isao and Hamilton, William L and Sato, Kei and Bhatt, Samir and Flaxman, Seth and James, Leo C and Corti, Davide and Piccoli, Luca and Barclay, Wendy S and Rakshit, Partha and Agrawal, Anurag and Gupta, Ravindra K}
}
