MOSCOW (PA) – Russia’s Ministry of Health agreed on Wednesday to reduce the size of a study of an internally developed coronavirus vaccine and stop enrolling volunteers.
The decision comes a week after developers said enrollment in the study has slowed since Russia began administering the Sputnik V vaccine, while the late-stage study continues. They also mentioned ethical concerns about providing a simulator to volunteers. The size of the study was reduced to about 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 mannequin shots discovered it and were vaccinated.
If a large number of placebo volunteers drop out, this 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 gather (necessary) statistics,” she said.
Russia has been widely 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 of 40,000 volunteers was announced.
Despite warnings awaiting the results of the study, Russian authorities began offering them to people at risk groups – such as medical workers and teachers – within weeks of approval.
President Vladimir Putin, who publicly hailed Sputnik V, ordered the Russian government to launch a large-scale immunization campaign this month. By mid-December, more than 150,000 people had been vaccinated, according to Gintsburg.
In a statement, the Ministry of Health said that the interim data of the study on the safety and efficacy of the vaccine were taken into account as part of the decision to reduce the size of the study. The ministry said the study would continue and participants would be monitored for at least another six months.
Gintsburg suggested administering the vaccine to all volunteers who received the placebo vaccine, but the ministry said there would be no “unblinding” of the study at this time. In other words, volunteers will not be told if they have received real or fictitious vaccines.
Kirill Dmitriev, head of the Russian direct investment fund that funded Sputnik V, said US physician Johnson & Johnson had recently downsized his vaccine study.
The developers of Sputnik V said the data suggest that the vaccine was 91% effective, a finding based on 78 coronavirus infections among nearly 23,000 participants. There are far fewer cases than Western drug manufacturers have accumulated during the final tests before analyzing how well their candidate has performed. Also, no important demographic and other details of the study were published.
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 Russia’s Inbio Ventures investment fund.
“We have no data on the proven effectiveness of the vaccine, other than what Gintsburg and the Russian Direct Investment Fund say,” Yasny said.