An interim analysis of data from a phase 3 clinical trial of Russia's two-dose Gam-COVID-Vac (Sputnik V) coronavirus vaccine involving nearly 20,000 adult volunteers suggests an efficacy of 91.6% against symptomatic infection.In the randomized, controlled, double-blind study, published today in The Lancet, researchers from the Ministry of Health of the Russian Federation in Moscow randomly assigned 19,866 participants at 25 hospitals and clinics in a 3:1 ratio to receive either the adenovirus-based vaccine or a placebo from Sep 7 to Nov 24, 2020.
A 0.5-milliliter (mL) dose was given, followed by a second dose 21 days later.High efficacy in older recipientsAfter the second dose, 16 of 14,964 (0.1%) of vaccine group participants tested