Russian COVID-19 vaccine safe, induces antibody response in small trials: Study

Russia's 'Sputnik V' COVID-19 vaccine, approved in country last month, produced antibody response in all participants with serious verse events in small human trials, according to first peer-reviewed results of preventive published in Lancet journal on Friday.

Results from early-phase n-randomised vaccine trials in a total of 76 people show that two formulations of vaccine have a good safety profile detected over 42 days, and induce antibody responses in all participants within 21 days.

Secondary outcomes from trial suggest vaccine, approved last month by Russia, also produces a T cell response within 28 days, researchers said.

two-part vaccine includes recombinant human evirus 26 (r26-S) and recombinant human evirus 5 (r5-S), which have been modified to express SARS-CoV-2 spike protein.

eviruses, which usually cause common cold, are also weakened so that y cant replicate in human cells and cant cause disease, according to researchers.

se vaccines aim to stimulate both arms of immune system -- antibody and T cell responses -- so y attack virus when it is circulating in body, and also attack cells infected by SARS-CoV-2.

"When evirus vaccines enter people’s cells, y deliver SARS-CoV-2 spike protein genetic code, which causes cells to produce spike protein," said study le author Denis Loguv, from Gamaleya National Research Centre for Epidemiology and Microbiology, Russia.

"This helps teach immune system to recognise and attack SARS-CoV-2 virus. To form a powerful immune response against SARS-CoV-2, it is important that a booster vaccination is provided," Loguv said.

trials took place in two hospitals in Russia, and were open-label and n-randomised, meaning that participants knew that y were receiving vaccine and were t assigned by chance to different treatment groups.

trials involved healthy ults d 18-60 years, who self-isolated as soon as y were registered, and remained in hospital for first 28 days of trial from when y were first vaccinated.

In phase 1 of each trial, participants received one component of two-part vaccine -- four groups of nine participants were given frozen or freeze-dried r26-S or r5-S component.

In phase 2, which began earlier than five days after phase 1 trial began, participants received full two-part vaccine.

re were 20 participants each in frozen and freeze-dried vaccine groups, Lancet study ted.

To compare post-vaccination immunity with natural immunity formed by infection with SARS-CoV-2, authors obtained convalescent plasma from 4,817 people who h recovered from mild or moderate COVID-19, y said.

Both vaccine formulations were safe over 42-day study period and well tolerated, according to study.

most common verse events were pain at injection site, hyperrmia, heache, asnia (weakness or lack of energy), and muscle and joint pain.

authors te that se verse effects are also seen with or vaccines, particularly those based on recombinant viral vectors.

Responding to findings, Naor Bar-Zeev from Johns Hopkins Bloomberg School of Public Health, US, who was t involved in study said trial results are encouraging but small on scale.

" immugenicity bodes well, although thing can be inferred on immugenicity in older groups, and clinical efficacy for any COVID-19 vaccine has t yet been shown… Showing safety will be crucial with COVID-19 vaccines, t only for vaccine acceptance but also for trust in vaccination broly," Bar-zeev said.

authors te some limitations to ir study, including that it h a short follow-up (42 days), it was a small study, some parts of phase 1 trials included only male volunteers, and re was placebo or control vaccine.

In dition, y te that despite planning to recruit healthy volunteers d 18–60 years, in general, ir study included fairly young volunteers (in ir 20s and 30s, on aver).

y say that more research is needed to evaluate vaccine in different populations, including older groups, individuals with underlying medical conditions, and people in at-risk groups.

Explaining next steps of ir research, Professor Alexander Gintsburg, from Gamaleya National Research Centre for Epidemiology and Microbiology said phase 3 clinical trial of vaccine has been approved on August 26, 2020.

"It is planned to include 40,000 volunteers from different and risk groups, and will be undertaken with constant monitoring of volunteers through an online application," Gintsburg ded.