In a comment published alongside the Lancet article, professors Ian Jones and Polly Roy reportedly said: "The development of the Sputnik V vaccine has been criticised for unseemly haste, corner cutting, and an absence of transparency".
"But the outcome reported here is clear and the scientific principle of vaccination is demonstrated, which means another vaccine can now join the fight to reduce the incidence of COVID-19".
Kremlin spokesman Dmitry Peskov said that Russian Federation is working to increase production of its homemade Sputnik V vaccine in foreign countries.
These results are based on Phase 3 trials of the vaccine in which 20,000 people had participated.
Sputnik V had been approved earlier in Russia, Belarus, Argentina, Bolivia, Serbia, Algeria, Palestine, Venezuela, Paraguay, Turkmenistan, Hungary, UAE, Iran, Republic of Guinea, Tunisia and Armenia.
"That is the only condition", she added.
As the press service of the ministry specified, talks between Brazilian health officials and representatives of the Gamaleya National Research Center for Epidemiology and Microbiology of the Russian Healthcare Ministry that developed Sputnik V and of India's Bharat Biotech that developed Covaxin are scheduled for Friday.
In addition to Gam-COVID-Vac, the country has registered a second vaccine, called EpiVacCorona, which contains synthesized SARS-CoV-2 peptides.
"It is not a matter of having only certain nationalities of companies, absolutely not", he said, adding that the EU Commission welcomes all initiatives that lead to building production capacity. "And we need all the safe effective vaccines we can get".
Mr Dmitriev mooted a partnership with other laboratories, while Merkel has proposed German aid for potential "joint production".
"In the very near future, there are plans to establish production in foreign countries, which will satisfy the demand from more and more countries", he told reporters a day after The Lancet published the efficacy results.
The study included more than 2,100 people over age 60 and the vaccine appeared to be about 92 percent effective in them.
The two-dose regimen of Sputnik V is administered 21 days apart.
Sputnik V is one of the three vaccines in the world with efficacy of over 90% against Covid-19.
The authors noted however that efficacy was calculated only on symptomatic cases and said more research would be needed to assess its effects on asymptomatic patients.
Mr Logunov said that the Sputnik V vaccine can be easily transported and is suitable for long storage without any special conditions. The authors explain that using a different adenovirus vector for the booster vaccination may help create a more powerful immune response (compared with using the same vector twice), as it minimises the risk of the immune system developing resistance to the initial vector.