NEW DELHI: The vaccine effectiveness of Covishield against COVID-19 infection in fully vaccinated individuals was found to be 63 per cent between April and May when the second wave was at its peak in India, according to a new study.
It was published in 'The Lancet Infectious Diseases' journal and it included a comparison between 2,379 cases of confirmed SARS-CoV-2 infection and 1,981 controls.
The vaccine's effectiveness against SARS-CoV-2 infection in fully vaccinated individuals was found to be 63 per cent.
The Science and Technology Ministry shared the study in an official statement.
"More importantly, the scientists also observed that the spike-specific T-cell responses were conserved against both the delta variant and wild-type SARS-CoV-2.
Such cellular immune protection might compensate for waning humoral immunity against the virus variants and prevent moderate-to-severe disease and need for hospitalisation," the study said.
The ministry said this study provides comprehensive data on the real-world vaccine effectiveness and immunological response to vaccination which should help guide policy.
A multi-institutional team of Indian researchers led by Translational Health Science and Technology Institute (THSTI) evaluated the real-world vaccine effectiveness of Covishield during the SARS-CoV-2 infection surge between April and May, 2021, in India.
They also assessed neutralising activity and cellular immune responses against the variants in healthy vaccinated persons to understand the mechanisms of protection.