MOSCOW (AP) – The Russian Ministry of Health agreed on Wednesday to reduce the scope of an investigation into a domestically developed coronavirus vaccine and to stop the enrollment of volunteers.
The decision comes a week after the developers said the enrollment of trial volunteers has been delayed since Russia began dispensing the Sputnik V vaccine while the investigation was still ongoing at a late stage. They also cited ethical concerns about giving some volunteers a dummy injection. The study size was reduced to approximately 31,000 from 40,000 participants.
Alexander Gintsburg, head of the Gamaleya Center, the state-run medical research institute that developed Sputnik V, said many of those who received fake injections discovered it and got it vaccinated.
If large numbers of volunteers in the placebo group drop out, it could affect the results, said Svetlana Zavidova, executive director of the Russian Association of Clinical Trials Organizations.
“They just won’t be able to collect (the necessary) statistics,” she said.
Russia was heavily criticized for giving regulatory approval to Sputnik V in August after the vaccine was tested on only a few dozen people. Two weeks later, the study with 40,000 volunteers was announced.
Despite warnings to wait for the results of the investigation, the Russian authorities began offering it to people in high-risk groups – such as medical staff and teachers – within weeks of approval.
President Vladimir Putin, who has publicly praised Sputnik V, has ordered the Russian government to launch a large-scale vaccination campaign this month. According to Gintsburg, more than 150,000 people had been vaccinated by mid-December.
In a statement, the Department of Health said that interim study data on the safety and effectiveness of the vaccine was considered part of the decision to reduce the study size. The ministry said the study would continue and the participants will be followed for at least another six months.
Gintsburg had proposed giving the vaccine to all volunteers who received the placebo injection, but the ministry said the study would not be “unblinded” at this point. In other words, volunteers are not told whether they received real or fake vaccines.
Kirill Dmitriev, head of the Russian Direct Investment Fund that funded Sputnik V, noted that US drug company Johnson & Johnson has recently reduced the scope of its vaccine research.
The developers of Sputnik V have said data suggests the vaccine was 91% effective, a conclusion based on 78 coronavirus infections among nearly 23,000 participants. That’s far fewer cases than Western drugmakers collected during the latest tests before analyzing how well their candidate worked. Important demographic and other details from the study have also not been released.
Western vaccine developers have released much more information, while much about the Russian vaccine is currently unknown, said Ilya Yasny, head of scientific research at Russian investment fund Inbio Ventures.
“We have no data on the vaccine’s proven effectiveness, apart from what Gintsburg and the Russian Direct Investment Fund say,” said Yasny.