Effectiveness of BBV152/Covaxin and AZD1222/Covishield vaccines against severe COVID-19 and B.1.617.2/Delta variant in India, 2021: a multi-centric hospital-based case-control studyTarun Bhatnagar, M Lanord Stanley Jawahar, Manickam Ponnaiah et al.|International Journal of Infectious Diseases|2022Cited by 44