Russia’s Sputnik V vaccine was 91.6% effective in preventing people from developing Covid-19, according to peer-reviewed results from its late-stage clinical trial published yesterday in The Lancet international medical journal.
Sputnik V was approved in Russia months before results from its final-stage clinical trials were published, leading to scepticism from experts. But the new analysis of data from 20,000 participants in Phase 3 trials suggests that the two-dose vaccination offers more than 90% efficacy against symptomatic COVID-19.
The results suggest Sputnik V is among the top-performing vaccines, along with the Pfizer/BioNTech and Moderna jabs that also reported efficacy exceeding 90%.
“The development of the Sputnik V vaccine has been criticised for unseemly haste, corner-cutting, and an absence of transparency,” said an independent Lancet commentary by Ian Jones of the University of Reading and Polly Roy of the London School of Hygiene and Tropical Medicine. “But the outcome reported here is clear and the scientific principle of vaccination is demonstrated, which means another vaccine can now join the fight to reduce the incidence of Covid-19.”
The trial involved giving 14,964 participants in the vaccine group and 4,902 in the placebo group two jabs 21 days apart. Those taking part were tested for COVID-19 at enrolment into the trial, again when they had the second dose and then after that if they reported symptoms. From the second dose, 16 cases of symptomatic COVID-19 were confirmed in the vaccine group and 62 cases were reported in the placebo group, giving an efficacy equivalent to 91.6%.
There were 2,144 volunteers over 60 in the trial and the shot was shown to be 91.8% effective when tested on this older group, with no serious side-effects reported that could be associated with Sputnik V, The Lancet summary said. The vaccine was also found to be 100% effective against moderate or severe Covid-19, as there were no such cases among the group of 78 participants who were infected and symptomatic at 21 days after the first shot was administered.
Sputnik V uses two different disarmed strains of the adenovirus, a virus that causes the common cold, as vectors to deliver the vaccine dose. Developers said that using a different adenovirus vector for the booster vaccination minimises the risk of the immune system developing resistance to the initial vector, so it may help create a more powerful response.
Several countries around the world have already registered Sputnik V, according to the Russian Direct Investment Fund which helped develop the vaccine, including Belarus, Venezuela, Bolivia and Algeria. Russia has already shared data from its Phase 3 trial with regulators in many countries and has begun the process of submitting it to the European Medicines Agency (EMA) for approval in the European Union.