%0 Journal Article %J Science %D 2021 %T Genomic characterization and epidemiology of an emerging SARS-CoV-2 variant in Delhi, India. %A Dhar, Mahesh S %A Marwal, Robin %A Vs, Radhakrishnan %A Ponnusamy, Kalaiarasan %A Jolly, Bani %A Bhoyar, Rahul C %A Sardana, Viren %A Naushin, Salwa %A Rophina, Mercy %A Mellan, Thomas A %A Mishra, Swapnil %A Whittaker, Charles %A Fatihi, Saman %A Datta, Meena %A Singh, Priyanka %A Sharma, Uma %A Ujjainiya, Rajat %A Bhatheja, Nitin %A Divakar, Mohit Kumar %A Singh, Manoj K %A Imran, Mohamed %A Senthivel, Vigneshwar %A Maurya, Ranjeet %A Jha, Neha %A Mehta, Priyanka %A A, Vivekanand %A Sharma, Pooja %A Vr, Arvinden %A Chaudhary, Urmila %A Soni, Namita %A Thukral, Lipi %A Flaxman, Seth %A Bhatt, Samir %A Pandey, Rajesh %A Dash, Debasis %A Faruq, Mohammed %A Lall, Hemlata %A Gogia, Hema %A Madan, Preeti %A Kulkarni, Sanket %A Chauhan, Himanshu %A Sengupta, Shantanu %A Kabra, Sandhya %A Gupta, Ravindra K %A Singh, Sujeet K %A Agrawal, Anurag %A Rakshit, Partha %A Nandicoori, Vinay %A Tallapaka, Karthik Bharadwaj %A Sowpati, Divya Tej %A Thangaraj, K %A Bashyam, Murali Dharan %A Dalal, Ashwin %A Sivasubbu, Sridhar %A Scaria, Vinod %A Parida, Ajay %A Raghav, Sunil K %A Prasad, Punit %A Sarin, Apurva %A Mayor, Satyajit %A Ramakrishnan, Uma %A Palakodeti, Dasaradhi %A Seshasayee, Aswin Sai Narain %A Bhat, Manoj %A Shouche, Yogesh %A Pillai, Ajay %A Dikid, Tanzin %A Das, Saumitra %A Maitra, Arindam %A Chinnaswamy, Sreedhar %A Biswas, Nidhan Kumar %A Desai, Anita Sudhir %A Pattabiraman, Chitra %A Manjunatha, M V %A Mani, Reeta S %A Arunachal Udupi, Gautam %A Abraham, Priya %A Atul, Potdar Varsha %A Cherian, Sarah S %X

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; ×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.

%B Science %P eabj9932 %8 2021 Oct 14 %G eng %R 10.1126/science.abj9932