1 min read.Updated: 30 Nov 2021, 02:54 PM ISTLivemint
The Lancet study found that the Covishield vaccine effectiveness in fully vaccinated individuals was 63%.
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A study published in reputed medical journal Lancet found that Serum Institute's Covishield vaccine proved effective in the height of second wave, driven largely by the Delta variant.
A multi-institutional team of Indian researchers evaluated the real-world vaccine effectiveness of Covishield during the coronavirus surge between April and May this year, the months when India was gasping for breath.
They assessed the neutralising activity and cellular immune responses against the variants in healthy vaccinated persons to understand the mechanisms of protection.
The study found that the vaccine effectiveness against the Covid infection in fully vaccinated individuals was 63%. More importantly, the efficacy was higher at 81% against moderate-to-severe disease.
The scientists also observed that the spike-specific T-cell responses were conserved against both the Delta variant and wild-type virus.
"Such cellular immune protection might compensate for waning humoral immunity against the virus variants and prevent moderate-to-severe disease and need for hospitalisation. This study provides the comprehensive data on the real-world vaccine effectiveness and immunological response to vaccination which should help guide policy," the study noted.
Coronavirus has affected more than 200 million people causing more than 5 million deaths worldwide as per the WHO statistics. The rise in mutant variants has led to concerns regarding vaccine effectiveness.