In:
BMJ Global Health, BMJ, Vol. 7, No. 5 ( 2022-05), p. e008271-
Abstract:
This study aimed to determine the effectiveness of Covishield vaccine among residents of congregate residential facilities. Design A prospective cohort study in congregate residential facilities. Setting Dharamshala, Himachal Pradesh, India, from December 2020 to July 2021. Participants Residents of all ages in seven facilities—three monasteries, two old age homes and two learning centres—were enrolled. Exposures First and second doses of Covishield vaccine against SARS-CoV-2 infection. Main outcomes measures Primary outcome was development of COVID-19. Secondary outcome was unfavourable outcomes, defined as a composite of shortness of breath, hospitalisation or death. Vaccine effectiveness (%) was calculated as (1−HR)×100. Results There were 1114 residents (median age 31 years) participating in the study, 82% males. Twenty-eight per cent (n=308/1114) were unvaccinated, 50% (n=554/1114) had received one dose and 23% (n=252/1114) had received two doses of Covishield. The point prevalence of COVID-19 for the facilities ranged from 11% to 57%. Incidence rates (95% CI) of COVID-19 were 76 (63 to 90)/1000 person-months in the unvaccinated, 25 (18 to 35)/1000 person-months in recipients of one dose and 9 (4 to 19)/1000 person-months in recipients of two doses. The effectiveness of first and second doses of Covishield were 71% (adjusted HR (aHR) 0.29; 95% CI 0.18 to 0.46; p 〈 0.001) and 80% (aHR 0.20; 95% CI 0.09 to 0.44; p 〈 0.001), respectively, against SARS-CoV-2 infection and 86% (aHR 0.24; 95% CI 0.07 to 0.82; p=0.023) and 99% (aHR 0.01; 95% CI 0.002 to 0.10; p 〈 0.001), respectively, against unfavourable outcome. The effectiveness was higher after 14 days of receiving the first and second doses, 93% and 98%, respectively. Risk of infection was higher in persons with chronic hepatitis B (aHR 1.78; p=0.034) and previous history of tuberculosis (aHR 1.62; p=0.047). Conclusion Covishield was effective in preventing SARS-CoV-2 infection and reducing disease severity in highly transmissible settings during the second wave of the pandemic driven by the Delta variant.
Type of Medium:
Online Resource
ISSN:
2059-7908
DOI:
10.1136/bmjgh-2021-008271
Language:
English
Publisher:
BMJ
Publication Date:
2022
detail.hit.zdb_id:
2851843-3
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