Covishield 63.1% effective against delta strain: Study

Aditi Tandon
Tribune News Service
New Delhi, November 26

Covishield, the primary component of India’s Covid-19 vaccine drive, has been found to be highly effective against the Sars-Cov2 infection caused by the virulent delta strain that devastated the country at the height of the second wave.

A collaboration of Indian scientists published the real world data on Covishield effectiveness on Friday, and concluded that the Serum Institute manufactured shot was 63.1 per cent effective against the delta strain.

This is more than the real world effectiveness of Covaxin against delta, which has been found to be 50 per cent.

In the study, published in journal Elsevier on Friday, the authors report a real-world effectiveness of 63.1 per cent for complete vaccination with the Covishield against laboratory-confirmed SARS-CoV-2 infection during the recent surge of Covid-19 cases caused by the delta variant in India.

Studies from England and Scotland earlier reported the effectiveness of 60-67 per cent for the vaccine against infection by the delta variant.

The delta variant has been shown to be 97 per cent more transmissible than wild-type SAR-CoV-2 and has emerged as the dominant Variant of Concern (VOC) across the world.

Breakthrough infections due to the delta variant have been reported after vaccination with mRNA vaccines.

“Our primary outcome to determine real-world vaccine effectiveness of two doses of Covishield vaccine against laboratory confirmed SARS-CoV-2 infection and secondary outcome was vaccine effectiveness of a single dose of the vaccine against SARS-CoV-2 infection and vaccine effectiveness of a single dose and complete vaccination against moderate-to-severe disease among individuals infected with SARS-CoV-2,” scientists said in a research published on Friday.

Scientists from the Biotechnology department’s Translational Health Science and Technology Institute Faridabad were part of the study.