Russia's Sputnik V shot is less effective against the 501Y.V2 Covid-19 variant, first discovered in South Africa, but still does better than other vaccines, the lead scientist behind it was quoted as saying on Friday.

"With regards to the 'South African' variant, the effectiveness of the antibodies produced by Sputnik V, like all other vaccines, against it declines," Alexander Gintsburg said in a interview with the Interfax news agency.

He said that Sputnik V was tested against 501Y.V2 and the British strain, as well as the original strain, first detected in China's Wuhan province, by laboratories in the United States. The labs used blood samples collected from people vaccinated with Sputnik V in Argentina, Gintsburg said.

Underlining that Russian researchers played no part in the lab tests, Gintsburg said that the results in trials of Sputnik V against the Wuhan strain confirmed what his team at Moscow's Gamaleya Institute found.

"It has also been shown that of all the vaccines currently in use in the world, Sputnik V... is best at neutralising the 'British' variant well," Gintsburg said.

Though the antibody response against the 501Y.V2 variant was less intense, the decline was significantly smaller than the drop other vaccines showed, Gintsburg was cited as saying.