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.
Int J Infect Dis
; 122: 693-702, 2022 Sep.
Article
in English
| MEDLINE | ID: covidwho-1936536
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.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Influenza Vaccines
/
COVID-19
Type of study:
Experimental Studies
/
Observational study
/
Prognostic study
/
Randomized controlled trials
Topics:
Vaccines
/
Variants
Limits:
Humans
Language:
English
Journal:
Int J Infect Dis
Journal subject:
Communicable Diseases
Year:
2022
Document Type:
Article
Affiliation country:
J.ijid.2022.07.033
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