¹Centre for Community Medicine, All India Institute of Medical Sciences, New Delhi, India
²Department of Biostatistics, All India Institute of Medical Sciences, New Delhi, India
³Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
⁴Department of Medical Oncology, Dr B.R.A Institute–Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India
⁵Division of Pedodontics and Preventive Dentistry, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India.
⁶Department of Pharmacology, All India Institute of Medical Sciences, New Delhi, India
⁷Department of Gastroenterology & Human Nutrition, All India Institute of Medical Sciences, New Delhi, India.
⁸Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
⁹Department of Hospital Administration, All India Institute of Medical Sciences, New Delhi, India
¹⁰Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
¹¹Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
¹²Department of Pulmonary Critical Care and Sleep Medicine, All India Institute of Medical Sciences, New Delhi, India

COVID Reinfection AIIMS Consortiumand the

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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.

Abstract

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 <15 days after the second dose), or unvaccinated. The incidence density of COVID-19 reinfection per 100 person-years was computed, and events from March 3, 2020, to June 18, 2021, were included for analysis. Unadjusted and adjusted hazard ratios (HRs) were estimated using a Cox proportional hazards model. Estimated vaccine effectiveness (1 − adjusted HR) was reported.

Results Among 15 244 HCWs who participated in the study, 4978 (32.7%) were diagnosed with COVID-19. The mean (SD) age was 36.6 (10.3) years, and 55.0% were male. The reinfection incidence density was 7.26 (95% CI: 6.09-8.66) per 100 person-years (124 HCWs [2.5%], total person follow-up period of 1696 person-years as time at risk). Fully vaccinated HCWs had lower risk of reinfection (HR, 0.14 [95% CI, 0.08-0.23]), symptomatic reinfection (HR, 0.13 [95% CI, 0.07-0.24]), and asymptomatic reinfection (HR, 0.16 [95% CI, 0.05-0.53]) compared with unvaccinated HCWs. Accordingly, among the 3 vaccine categories, reinfection was observed in 60 of 472 (12.7%) of unvaccinated (incidence density, 18.05 per 100 person-years; 95% CI, 14.02-23.25), 39 of 356 (11.0%) of partially vaccinated (incidence density 15.62 per 100 person-years; 95% CI, 11.42-21.38), and 17 of 1089 (1.6%) fully vaccinated (incidence density 2.18 per 100 person-years; 95% CI, 1.35-3.51) HCWs. The estimated effectiveness of BBV152 against reinfection was 86% (95% CI, 77%-92%); symptomatic reinfection, 87% (95% CI, 76%-93%); and asymptomatic reinfection, 84% (95% CI, 47%-95%) among fully vaccinated HCWs. Partial vaccination was not associated with reduced risk of reinfection.

Conclusions and Relevance These findings suggest that BBV152 was associated with protection against both symptomatic and asymptomatic reinfection in HCWs after a complete vaccination schedule, when the predominant circulating variant was B.1.617.2.

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Article Information

Accepted for Publication: November 5, 2021.

Published: January 7, 2022. doi:10.1001/jamanetworkopen.2021.42210

Corresponding Author: Randeep Guleria, DM, Director, All India Institute of Medical Sciences, Ansari Nagar East, Delhi-110029, India (director.aiims@gmail.com).

The COVID Reinfection AIIMS Consortium Authors: Aman Dua, MPH; Shafi Ahmad, MDS; Ramadass Sathiyamoorthy, MD; Ajay Sharma, BSc; Tabbu Sakya, MCA; Vikas Gaur, PhD; Shilpi Chaudhary, PhD; Swetambri Sharma, MSc; Divya Madan, MSc; Anvita Gupta, MSc; Shubi Virmani, MDS; Arti Gupta, MSc; Nidhi Yadav, MSc; Surbhi Sachdeva, MCom; Shilpi Sharma, BA; Sachin Singh, BSc; Abhimanyu Pandey, MPharma; Mukesh Singh, PhD; Divashree Jhurani, MSc; Swarnabha Sarkar, MSc; Amol Kumar Lokade, MDS; Atif Mohammad, MDS; Sabitri Pandit, BTech; Ritu Dubey, MA; Ajay Kumar Singh, MA; Naveen Gohar, BA; Divyansh Soni, MBBS; Arunangshu Bhattacharyya, MBBS; Sabin Rai, MBBS; Snikitha Tummala, MBBS; Ishan Gupta, MBBS; Sakshi Shukla, MSc.

Affiliations of The COVID Reinfection AIIMS Consortium Authors: Centre for Community Medicine, All India Institute of Medical Sciences, New Delhi, India (Dua, Ahmad, Sathiyamoorthy, A. Sharma, Sakya); Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India (Dubey, A. K. Singh, Gohar); Department of Medical Oncology, Dr B.R.A Institute–Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India (Gaur, Chaudhary, Swetambri Sharma); Division of Pedodontics and Preventive Dentistry, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India. (Lokade, Mohammad); Department of Gastroenterology & Human Nutrition, All India Institute of Medical Sciences, New Delhi, India. (Madan, Anvita Gupta, Virmani, Arti Gupta, Yadav, Sachdeva, Shilpi Sharma, S. Singh, Pandey, M. Singh, Jhurani); Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India (Shukla); Department of Physiology, All India Institute of Medical Sciences, New Delhi, India (Sarkar); Medical Device Monitoring Center, Department of Pharmacology, All India Institute of Medical Sciences, New Delhi, India (Pandit); Academic Section, All India Institute of Medical Sciences, New Delhi, India (Soni, Bhattacharyya, Rai, Tummala, I. Gupta).

Author Contributions: Drs Malhotra and Mani had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Drs Malhotra and Mani are joint first authors.

Concept and design: Malhotra, Mani, Lodha, Bakhshi, Mathur, Sankar, P. Kumar, A. Kumar, Ahuja, Sinha, Guleria, Ahmad.

Acquisition, analysis, or interpretation of data: Malhotra, Mani, Lodha, Bakhshi, Mathur, P. Gupta, Kedia, P. Kumar, Dua, Ahmad, Sathiyamoorthy, A. Sharma, Sakya, Gaur, Chaudhary, Swetambri Sharma, Madan, Anvita Gupta, Virmani, Arti Gupta, Yadav, Sachdeva, Shilpi Sharma, S. Singh, Pandey, M. Singh, Jhurani, Sarkar, Lokade, Mohammad, Pandit, Dubey, A. Singh, Gohar, Soni, Bhattacharyya, Rai, Tummala, I. Gupta, Shukla.

Drafting of the manuscript: Malhotra, Mani, Bakhshi, Mathur, P. Kumar, Ahuja, Sinha, Guleria, Dua, Ahmad, Sathiyamoorthy, A. Sharma, Sakya, Gaur, Chaudhary, Swetambri Sharma, Madan, Anvita Gupta, Virmani, Arti Gupta, Yadav, S. Singh, Pandey, M. Singh, Jhurani, Sarkar, Lokade, Mohammad, Pandit, Dubey, A. Singh, Gohar, Soni, Bhattacharyya, Rai, Tummala, I. Gupta, Shukla.

Critical revision of the manuscript for important intellectual content: Malhotra, Mani, Lodha, Bakhshi, Mathur, P. Gupta, Kedia, Sankar, A. Kumar, Sinha, Guleria, Sachdeva, Shilpi Sharma.

Statistical analysis: Malhotra, Mani, Lodha, Bakhshi, Sankar, Ahmad, Gaur, Soni.

Obtained funding: Malhotra, Mathur.

Administrative, technical, or material support: Malhotra, Mani, Lodha, Bakhshi, Mathur, P. Gupta, Sankar, P. Kumar, A. Kumar, Sinha, Guleria, Dua, Ahmad, Sathiyamoorthy, A. Sharma, Sakya, Gaur, Chaudhary, Swetambri Sharma, Madan, Anvita Gupta, Virmani, Arti Gupta, Yadav, Sachdeva, Shilpi Sharma, S. Singh, Pandey, M. Singh, Jhurani, Sarkar, Lokade, Mohammad, Pandit, Dubey, A. Singh, Gohar, Bhattacharyya, Rai, Tummala, I. Gupta, Shukla.

Supervision: Malhotra, Mani, Bakhshi, Mathur, Sankar, A. Kumar, Ahuja, Sinha, Guleria, Ahmad.

Conflict of Interest Disclosures: None reported.

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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

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