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 study
Tarun Bhatnagar, Sirshendu Chaudhuri, Manickam Ponnaiah, Pragya D. Yadav, R. Sabarinathan, Rima R. Sahay, Faheem Ahmed, S Aswathy, Pankaj Bhardwaj, Anil S. Bilimale, M Santhosh Kumar, M Logaraj, Uday Narlawar, C Palanivel, Prakash Patel, Sanjay K Rai, Vartika Saxena, Arvind Kumar Singh, Jeromie Wv Thangaraj, Ashwini Agarwal, Yasir Alvi, Anon Amoghashree, P Ashok, Dinesh Babu, Yogesh Bahurupi, Sangita Bhalavi, Priyamadhaba Behera, Priyanka Pandit Biswas, Jaykaran Charan, Nishant Kumar Chauhan, K. B. Chetak, Lalit Dar, Ayan Kumar Das, R Deepashree, Minakshi Dhar, Rahul Dhodapkar, TS Dipu, Mridu Dudeja, Manisha Dudhmal, Ravisekhar Gadepalli, Mahendra Kumar Garg, A V Gayathri, Akhil Dhanesh Goel, H. Basavana Gowdappa, Randeep Guleria, Manoj Kumar Gupta, Farzana Islam, Mannu Jain, Vineet Jain, M Lanord Stanley Jawahar, Rajendra Joshi, Shashi Kant, Sitanshu Sekhar Kar, Deepjyoti Kalita, Meenakshi Khapre, Satyendra Khichar, Sarika Kombade, Sunil Kohli, Abhinendra Kumar, Anil Kumar, Deepak Kumar, Kiran G Kulirankal, K V Leela, Triparna Majumdar, Baijayantimala Mishra, Puneet Misra, Sanjeev Misra, Prasanta Raghab Mohapatra, M Narayana Murthy, Dimpal A. Nyayanit, Manish Patel, Monika Pathania, Savita Patil, Binod Kumar Patro, Ramniwas Jalandra, Pragati Rathod, Naimesh Shah, Anita M. Shete, Deepak Shukla, M Shwethashree, Smita Sinha, Mahadevaiah Neelambike Sumana, Ashish Surana, Anjan Trikha, A Tejashree, Mahalingam Venkateshan, G Vijaykrishnan, Sarita Wadhava, Naveet Wig, Nivedita Gupta, Priya Abraham, Manoj V Murhekar
Abstract
OBJECTIVES: India introduced BBV152/Covaxin and AZD1222/Covishield vaccines in January 2021. We estimated the effectiveness of these vaccines against severe COVID-19 among individuals aged ≥45 years. METHODS: We did a multi-centric, hospital-based, case-control study between May and July 2021. Cases were severe COVID-19 patients, and controls were COVID-19 negative individuals from 11 hospitals. Vaccine effectiveness (VE) was estimated for complete (2 doses ≥ 14 days) and partial (1 dose ≥ 21 days) vaccination; interval between two vaccine doses and vaccination against the Delta variant. We used the random effects logistic regression model to calculate the adjusted odds ratios (aOR) with a 95% confidence interval (CI) after adjusting for relevant known confounders. RESULTS: We enrolled 1143 cases and 2541 control patients. The VE of complete vaccination was 85% (95% CI: 79-89%) with AZD1222/Covishield and 71% (95% CI: 57-81%) with BBV152/Covaxin. The VE was highest for 6-8 weeks between two doses of AZD1222/Covishield (94%, 95% CI: 86-97%) and BBV152/Covaxin (93%, 95% CI: 34-99%). The VE estimates were similar against the Delta strain and sub-lineages. CONCLUSION: BBV152/Covaxin and AZD1222/Covishield were effective against severe COVID-19 among the Indian population during the period of dominance of the highly transmissible Delta variant in the second wave of the pandemic. An escalation of two-dose coverage with COVID-19 vaccines is critical to reduce severe COVID-19 and further mitigate the pandemic in the country.