In the Phase 1 and 2 studies of the vaccine, called Sputnik V, all 76 study participants developed antibodies to the virus that causes Covid-19, according to Friday’s report in The Lancet.
The magnitude of the neutralizing antibody response was similar to the immune response people had after naturally recovering from Covid-19, according to the study.
The researchers also looked at the responses of T cells, another part of the immune system.
“”[Outcomes from] The study also suggests that the vaccines also elicit a T-cell response within 28 days, “the researchers wrote.
Larger attempts required
Scientists not involved in the study said that while the results are a positive sign, only larger phase 3 studies can confirm whether the vaccine actually prevents disease with Covid-1
“The data on the Russian vaccine studies in The Lancet are encouraging,” said Brendan Wren, professor of microbial pathogenesis at the London School of Hygiene and Tropical Medicine.
In the study, half of the participants developed a fever and 42% developed a headache. In addition, around 28% had weakness and 24% had joint pain.
The article did not say how long these side effects lasted, but rather said “most of the adverse events were mild”.
The vaccine was registered in Russia in August before going through large-scale studies. Researchers at the National Epidemiology and Microbiology Research Center in Gamaleya, Russia, received approval for a Phase 3 trial on Aug. 26, which is expected to include 40,000 volunteers, according to a press release from The Lancet.
According to Kirill Dmitriev, head of the Russian Direct Investment Fund (RDIF), which finances Russian vaccine research, researchers are already distributing the vaccine to risk groups.
Gamaleya uses adenoviruses in their Covid-19 vaccines. This is the same approach as the vaccine developed by the University of Oxford and AstraZeneca. The adenovirus provides genetic material for the spike protein found on the virus that causes Covid-19, and this genetic material is said to produce an immune response to the virus.
Adenoviruses can cause a variety of symptoms, including the common cold. The researchers manipulate the virus so that it does not multiply and cause disease.
The Gamaleya vaccine is given in two doses, and each dose uses a different adenovirus vector.
“There is a theoretical advantage to using two different viruses,” said Dr. Paul Offit, vaccinator at the University of Pennsylvania.
Naor Bar-Zeev, associate director of the International Vaccine Access Center at Johns Hopkins University, said in a linked comment that the studies were “encouraging but small,” according to The Lancet. Bar-Zeev was not involved in the Russian study, but was peer-reviewed.
Dmitriev, CEO of RDIF, said the trial results confirm the vaccine’s “high safety and effectiveness”, adding in a statement Friday that the results are “a strong response to skeptics who have inappropriately criticized the Russian vaccine”.
Mass trials begin next week
Russia previously announced that it would begin mass vaccinating citizens in October, and the country’s health ministry has announced that medical staff and teachers on the country’s front lines will be the first to be vaccinated.
Re-registration attempts with the vaccine will begin next week in Moscow, the city’s mayor Sergey Sobyanin said on Friday.
According to Sobyanin, who spoke to Russian President Vladimir Putin during a video conference, more than 5,000 people have already registered to take part in the trials.
Sobyanin also announced that he had been vaccinated with the first of the two vaccination shots.
According to surveys by the mayor, around half of Russian citizens are skeptical of the vaccine.
“According to the surveys, about half doubt whether they need to be vaccinated against coronavirus, whether it is sufficiently developed or not. Two months ago there were almost 90% skeptics,” said Sobyanin.
Without completed Phase 3 trials, Russia has not proven to the world that Sputnik V works, despite Dmitriev previously stated that several countries in Latin America, the Middle East, and Asia have expressed an interest in sourcing the vaccine.
CNN’s Zamira Rahim and Amy Woodyatt contributed to this report.