MOSCOW (AP) – The Russian Ministry of Health agreed Wednesday to reduce the size of a study of an internally developed coronavirus vaccine and to stop recruiting volunteers.
The decision was made a week after developers said the recruitment of study volunteers has slowed since Russia started distributing the Sputnik V vaccine while the final stage study was still in progress. They also cited ethical concerns about giving a false injection to some of the volunteers. The size of the study was reduced to around 31,000 out of 40,000 participants.
Alexander Gintsburg, head of the Gamaleya Center, the state medical research institute that developed Sputnik V, said that many who received false injections found out and were vaccinated.
If a large number of volunteers in the placebo group drop out, it could affect the results, said Svetlana Zavidova, executive director of the Association of Clinical Trials Organizations in Russia.
“They just won’t be able to collect the (necessary) statistics,” she said.
Russia was widely criticized for giving Sputnik V regulatory approval in August, after the vaccine was only tested on a few dozen people. Two weeks later, the study of 40,000 volunteers was announced.
Despite warnings of waiting for the results of the study, Russian authorities began offering it to people in high-risk groups – such as medical professionals and teachers – weeks after approval.
President Vladimir Putin, who publicly welcomed Sputnik V, ordered the Russian government this month to start a large-scale immunization campaign. In mid-December, more than 150,000 people were vaccinated, according to Gintsburg.
In a note, the Ministry of Health said that the study’s interim data on the safety and efficacy of the vaccine were considered part of the decision to downsize the study. The ministry said the study will continue and participants will be monitored for at least another six months.
Gintsburg suggested giving the vaccine to all volunteers who received the placebo injection, but the ministry said there would be no “untying” of the study at this time. In other words, volunteers will not be informed if they have received real or fake vaccines.
Kirill Dmitriev, head of the Russian Direct Investment Fund that financed Sputnik V, noted that American drugmaker Johnson & Johnson recently reduced the size of its vaccine test.
The developers of Sputnik V said the data suggested that the vaccine was 91% effective, a finding based on 78 coronavirus infections among about 23,000 participants. This is far less cases than Western pharmaceuticals accumulated during the final test before analyzing their candidate’s performance. Important demographic data and other details of the study were also not disclosed.
Western vaccine developers have released much more information, while much about the Russian vaccine remains unknown at this time, said Ilya Yasny, head of scientific research at Russian investment fund Inbio Ventures.
“We have no data on the vaccine’s proven effectiveness, other than what Gintsburg and the Russian Direct Investment Fund say,” said Yasny.