By Layal Liverpool
A medical worker prepares a syringe during vaccination with the Sputnik V vaccine against covid-19Dmitry FeoktistovTASS via Getty Images
Russia’s Sputnik V vaccine is 91.6 per cent effective at preventing symptomatic covid-19, preliminary results suggest. The vaccine has been submitted to European Union regulators for approval.
The data is based on interim results from a trial of 21,977 adults. Three-quarters of the participants were randomly assigned to receive two doses of the vaccine, the remainder were given a placebo.
Of the 14,964 people who received the vaccine, 16 developed symptomatic covid-19 compared with 62 out of 4902 in the placebo group. The results, published today in The Lancet, suggest efficacy was similar across all age groups, including among people over the age of 60.
The results look reassuring, says Naveed Sattar at the University of Glasgow, UK. “[There was] very good protection from infection, matched by evidence of good antibody responses in all age groups tested and good safety profiles,” he says.
The Gamaleya National Center of Epidemiology and Microbiology in Moscow, which developed the vaccine, has already submitted documents to the European Medicines Agency to apply for approval of the vaccine in the EU, says Kirill Dmitriev, director of the Russian Direct Investment Fund, which is funding the Sputnik V programme.
Germany’s health minister Jens Spahn recently hinted that covid-19 vaccines from Russia and China could be used in Europe to overcome a shortage of doses. “Regardless of the country in which a vaccine is manufactured, if they are safe and effective, they can help cope with the pandemic,” Spahn told German media on 31 January.
The Russian vaccine prompted concern among immunologists last year after it was approved in Russia in August before any detailed results from advanced clinical trials were released.
In November, early results of the Sputnik V vaccine had suggested it was 92 per cent effective at preventing symptomatic covid-19, although the data included only a small number of coronavirus infections – 20 trial participants of approximately 16,000 in the study had been diagnosed with covid-19 at the time.
“All our critics are sitting quiet at the moment,” Dmitriev said during a press conference on 2 February. “We have addressed all of the concerns […] Sputnik V has proven itself to be one of the most effective and safest vaccines of the world.” Sputnik V has already been approved in 15 countries, and this could increase to 25 countries by the end of this week, he said.
Sputnik V uses a two-dose, viral vector-based approach similar to the vaccine developed by the University of Oxford and AstraZeneca, for which a harmless virus, or “vector”, is used to transport the coronavirus spike protein into cells and provoke an immune response. However, whereas the two doses are identical in the Oxford/AstraZeneca vaccine, each dose in Sputnik V contains a slightly different vector. This is thought to be beneficial because the immune system can be so efficient that it eliminates the second dose too quickly if it is the same as the first, and therefore it doesn’t help to build an immune response, said Alexander Edwards at the University of Reading, UK, in a statement.
The Oxford/AstraZeneca vaccine was found to be 62 per cent effective when people were given two full doses 28 days apart, and up to 90 per cent effective in people who were accidentally given a half dose followed by a full dose.
The Sputnik V vaccine “appears even more effective” after two full doses than the Oxford/AstraZeneca one, said Julian Tang at the University of Leicester, UK, in a statement. However, the interim efficacy analysis on Sputnik V is based on an average follow-up time of only 48 days (compared with four months for the Oxford/AstraZeneca vaccine) and only included symptomatic cases of covid-19, he added.
Dmitriev said researchers at the Gamaleya institute are also investigating the effectiveness of the Sputnik V vaccine against new variants of the coronavirus, such as the highly transmissible virus variants first identified in the UK and South Africa.
Journal reference: The Lancet, DOI: 10.1016/S0140-6736(21)00234-8
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