According to the Lancet, Covishield’s vaccine efficacy was determined to be 63% in completely vaccinated persons

Covishield vaccine remained effective against moderate-to-severe COVID-19 infections even during the infection surge between April and May in India, a study published in Lancet Infectious Diseases journal said.

The Lancet study was designed to assess Covishield's real-world effectiveness amid India's severe surge in April and May, which wreaked havoc on the country's health system.

According to the Lancet, Covishiled’s vaccine efficacy was determined to be 63% in completely vaccinated persons.

The vaccine's efficiency was determined to be 81% during the moderate to severe disease phase, said the study.

“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,” a statement of the Ministry of Science and Technology said on Tuesday.

Also, assessed was the neutralising activity and cellular immune responses against the variants in healthy vaccinated persons to understand the mechanisms of protection.

Comparing 2379 cases of confirmed SARS-CoV-2 infection and 1981 controls, the vaccine effectiveness against SARS-CoV-2 infection in fully vaccinated individuals was found to be 63%, the statement added.

The vaccine effectiveness of complete vaccination against moderate-to-severe disease was much higher at 81%, it stated.

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, it added.

Such cellular immune protection might compensate for waning humoral immunity against the virus variants and prevent moderate-to-severe disease and need for hospitalization, the statement noted.

The study provides comprehensive data on the real-world vaccine effectiveness and immunological response to vaccination which should help guide policy, it mentioned.