Denis Logunov, deputy head of the Gamaleya Centre, was quoted by Russian news agency Tass as saying the effectiveness of the Sputnik V vaccine was 2.6 times lower against the variant first discovered in India.
But the Sputnik V jab is still around 90 per cent effective against the Delta variant, Mr Logunov said, compared with 92 per cent efficacy against the original variant.
“We see that there is a slight decrease in serum activity with regard to the delta variant – it is about 2.6 times for Sputnik V,” he said at a press conference.
He claimed that other vaccines produced outside of Russia had shown a bigger drop in efficacy, adding: “We’re optimistic … there is a fall, but the fall is insignificant.”
He also warned that the low numbers of Russians who are fully vaccinated – around 12 per cent of the population have received both doses – risked allowing the virus to mutate further.
I decided to take the Sputnik vaccine – but is it safe?
A recent study found that Pfizer jab recipients had almost five times fewer antibodies to protect against the Delta variant and that these antibody levels decreased with time and age.
The study, produced by the Francis Crick Institute and the National Institute for Health Research, noted that after a first dose, Pfizer jab recipients had 79 per cent antibody protection against the original strain, 50 per cent against the Alpha (Kent) variant, and only 32 per cent against the Delta variant. The efficacy increased sharply following a second dose.