Russia's Sputnik V vaccine against Covid-19 is around 83 per cent effective against the Delta variant of coronavirus, lower than previously thought, Health Minister Mikhail Murashko said.

Authorities blamed a surge in coronavirus cases in June and July on the more contagious Delta variant and the population's reluctance to get vaccinated despite shots being widely available.

The vaccine's developers in June said Sputnik V was around 90pc effective against the Delta variant.

“The latest results show that effectiveness is around 83pc,” the TASS news agency cited Murashko as saying.