After criticism last year for an early rollout, Russia’s Sputnik V coronavirus vaccine is 91.6% effective against symptomatic Covid-19 and 100% effective for preventing severe illness, according to an interim analysis of Phase 3 trial data published in the medical journal The Lancet on Tuesday.
The randomized, double-blind, placebo-controlled clinical trial includes data on 19,866 participants, of whom 14,964 received the vaccine and 4,902 received the placebo. There were 78 cases of Covid-19 among the trial participants, and only 16 of them had received the vaccine. The rest received a placebo, which does nothing.
The trial included 2,144 people over the age of 60, and a sub-analysis conducted on this group revealed the vaccine was well tolerated and had a similar efficacy of 91.8%.
Seventy serious adverse events were reported in 68 trial participants, including 45 in the vaccine group and 23 in the placebo group, but none were considered associated with the vaccination, according to the study. Most of the adverse events reported were mild, such as flu-like symptoms and pain at the injection site.
The analysis includes only symptomatic cases of Covid-19, and the authors note more research is needed to understand the vaccine’s efficacy against asymptomatic Covid-19, transmission and how long protection may last.
The vaccine is a two-dose adenoviral vector vaccine, with doses administered 21 days apart. With this type of vaccine, the adenovirus is altered so that it can deliver a piece of genetic material from another pathogen, such as the virus that causes Covid-19. It’s an approach similar to the vaccines developed by AstraZeneca and Johnson & Johnson.
Sputnik V uses two different vectors that are based on a human adenoviruses in separate shots. Researchers from Gamaleya National Research Centre for Epidemiology and Microbiology in Russia write that using a different adenovirus vector for the booster may create a more powerful immune response than using the same vector a second time, by minimizing the risk of immune system resistance.
Sputnik V only needs to be refrigerated and costs $10 per dose, according to the Russian Direct Investment Fund, which funded vaccine production and is responsible for selling it globally.
Some context: The vaccine is already approved in Russia, Belarus, Serbia, Argentina, Bolivia, Algeria, the Palestinian territories, Venezuela, Paraguay, Turkmenistan, Hungary, UAE, Iran, Guinea, Tunisia and Armenia. Sputnik V has so far been administered to more than 2 million people worldwide.
Russia drew criticism from scientific circles last year, when it announced the world's first approved coronavirus vaccine for public use in August -- before the crucial Phase 3 trials had been completed.
“The development of the Sputnik V vaccine has been criticised for unseemly haste, corner cutting, and an absence of transparency,” University of Reading Professor Ian Jones London School of Hygiene & Tropical Medicine Professor Polly Roy wrote in a commentary published in The Lancet Tuesday. They 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.”
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