In the race for a coronavirus vaccine, Russia was widely criticised for giving its Sputnik V jab regulatory approval in August after it had only been tested on a few dozen people.

An advanced study among tens of thousands started shortly after, but despite warnings urging them to wait for the results, authorities began offering it to people in high-risk groups such as medical workers and teachers within weeks.

In December, mass vaccinations with Sputnik V started in Russia, even though it is still undergoing the late-stage trial.

Now interim analysis of phase 3 of the trial, published by The Lancet, suggest the vaccine offers 91.6% efficacy against coronavirus – higher than that provided by AstraZeneca (60%), Johnson & Johnson (single shot, at 66%) and Novavax (89%)

“The development of the Sputnik V vaccine has been criticised for unseemly haste, corner cutting, and an absence of transparency,” noted Professor Ian Jones, University of Reading, and Professor Polly Roy, London School of Hygiene & Tropical Medicine (who were not involved in the study).

“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 findings are based on an analysis of data from nearly 20,000 participants, with three quarters receiving the vaccine and one quarter receiving a placebo. There were 16 coronavirus cases in the vaccine group after receiving the first dose, and 62 in the placebo group.

Four deaths were reported, none of which were considered related to the vaccine and most adverse effects were mild, including flu-like symptoms, pain at injection site and weakness or low energy.

The trial included 2,144 participants older than 60, with 91.8% vaccine efficiency for this group, indicating it to be particularly well tolerated and effective. The trial is ongoing and aims to include a total of 40,000 participants, with monitoring of safety and efficacy continuing.

Mass Sputnik V vaccination programmes are already underway in Belarus and Argentina.

Belarus conducted its own trial of the vaccine among 100 volunteers and gave it regulatory approval on December 21.

The UK has not secured access to the Russian vaccine.