Malhotra, Sumit, Mani, Kalaivani, Lodha, Rakesh, Bakhshi, Sameer, Mathur, Vijay Prakash, Gupta, Pooja, Kedia, Saurabh, Sankar, Jeeva, Kumar, Parmeshwar, Kumar, Arvind, Ahuja, Vineet, Sinha, Subrata, Guleria, Randeep, Dua, Aman, Ahmad, Shafi, Sathiyamoorthy, Ramadass, Sharma, Ajay, Sakya, Tabbu, Gaur, Vikas, Chaudhary, Shilpi, Sharma, Swetambri, Madan, Divya, Gupta, Anvita, Virmani, Shubi, Gupta, Arti, Yadav, Nidhi, Sachdeva, Surbhi, Sharma, Shilpi, Singh, Sachin, Pandey, Abhimanyu, Singh, Mukesh, Jhurani, Divashree, Sarkar, Swarnabha, Lokade, Amol Kumar, Mohammad, Atif, Pandit, Sabitri, Dubey, Ritu, Singh, Ajay Kumar, Gohar, Naveen, Soni, Divyansh, Bhattacharyya, Arunangshu, Rai, Sabin, Tummala, Snikitha, Gupta, Ishan, and Shukla, Sakshi
Key Points Question What are the rate of reinfection of SARS-CoV-2 among a cohort of health care workers (HCWs) and the estimated effectiveness of the inactivated whole virion vaccine BBV152 against reinfection? Findings In this cohort study of 4978 HCWs who were infected with SARS-CoV-2 from March 3, 2020, to June 18, 2021, the incidence density of reinfection was 7.26 per 100 person-years. A protective association of 86% against reinfection was observed among HCWs who completed the 2-dose schedule of BBV152 and for whom at least 15 days elapsed without reinfection after vaccination. Meaning The results of this study suggest that complete vaccination with BBV152 among HCWs in India is crucial, including in persons previously infected with SARS-CoV-2., Importance A surge of COVID-19 occurred from March to June 2021, in New Delhi, India, linked to the B.1.617.2 (Delta) variant of SARS-CoV-2. COVID-19 vaccines were rolled out for health care workers (HCWs) starting in January 2021. Objective To assess the incidence density of reinfection among a cohort of HCWs and estimate the effectiveness of the inactivated whole virion vaccine BBV152 against reinfection. Design, Setting, and Participants This was a retrospective cohort study among HCWs working at a tertiary care center in New Delhi, India. Exposures Vaccination with 0, 1, or 2 doses of BBV152. Main Outcomes and Measures The HCWs were categorized as fully vaccinated (with 2 doses and ≥15 days after the second dose), partially vaccinated (with 1 dose or 2 doses with, This cohort study assesses the SARS-CoV-2 reinfection rate and estimated effectiveness of the inactivated whole virion vaccine BBV152 against reinfection among health care workers in New Delhi, India.