Russia’s Sputnik V vaccine has produced strong results against new COVID-19 mutations in recent trials, researchers claim.
Denis Logunov, the deputy director of the Gamaleya centre in Russia, where the Sputnik V vaccine was developed, said the trial showed revaccination with the Russian vaccine “is working very well” against new COVID-19 mutations, including the UK and South African variants.
Results of the trial are expected to be published soon, but this was the first indication of how the tests were going.
So-called viral vector shots – such as Sputnik V and a shot developed by AstraZeneca – use harmless modified viruses as vehicles, or vectors, to carry genetic information that helps the body build immunity against future infections.
The revaccination used the same Sputnik V shot, based upon the same adenovirus vectors. The trial indicated this did not impact effectiveness, Mr Logunov said.
Some scientists have raised the possible risk that the body also develops immunity to the vector itself, recognising it as an intruder and trying to destroy it. But developers of Sputnik V disagreed this would pose long-term problems.
“We believe that vector-based vaccines are actually better for future revaccinations than vaccines based on other platforms,” Mr Logunov said.
He also added the researchers found antibodies specific to the vectors used by the shot – which could generate an anti-vector reaction and undermine the work of the shot itself – declined “as early as 56 days after vaccination”.
This conclusion was based on a trial of a vaccine against Ebola developed earlier by the Gamaleya Institute using the same approach as for the Sputnik V shot.
Vector immunity is not a new issue but has come under renewed scrutiny as companies including Johnson & Johnson anticipate regular coronavirus vaccinations, like annual influenza shots may be needed to combat new variants of the coronavirus.
Earlier this month, peer-reviewed interim results from the phase three trials showed two doses of Sputnik V are 91.6% effective against the virus.
President Vladimir Putin ordered a review by 15 March of Russian-produced vaccines for their effectiveness against new variants spreading in different parts of the world.
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