Russia's COVID-19 vaccine, Sputnik V, has shown 91.6 per cent efficacy in phase 3 trials with no serious side effects, as per an interim analysis published in The Lancet Journal.
About 20,000 participants participated in the phase-III trials, carried out at 25 hospitals and polyclinics in Moscow, Russia, with 75 per cent of them receiving the two-dose vaccine and 25 per cent getting placebo.
"This interim analysis of the phase-III trial of Gam-COVID-Vac showed 91.6 per cent efficacy against COVID-19 and was well tolerated in a large cohort," the researchers said.
The Gam-COVID-Vac, called Sputnik V, is a two-part vaccine that includes two adenovirus vectors - recombinant human adenovirus type 26 (rAd26-S) and recombinant human adenovirus type 5 (rAd5-S).
Four deaths were reported during the study, none of which were considered related to the vaccine. Besides, 70 episodes of serious adverse events were recorded in 68 participants across the two groups, but none of these events were considered related to the vaccine, the study said.
The vaccine was approved in Russia even before the release of phase 3 trials data.
Currently, 164 COVID-19 vaccine candidates are in clinical assessment (including 13 at phase 3), while 173 are in preclinical analysis.