Russia cuts size of COVID-19 vaccine study, stops enrollment

Russian President Vladimir Putin attends a meeting via video conference in Moscow, Russia, Wednesday, Dec. 23, 2020. (Mikhail Klimentyev, Sputnik, Kremlin Pool Photo via AP)
Russian President Vladimir Putin attends a meeting via video conference in Moscow, Russia, Wednesday, Dec. 23, 2020. (Mikhail Klimentyev, Sputnik, Kremlin Pool Photo via AP) (Sputnik)

MOSCOW – Russia’s Health Ministry agreed Wednesday to cut the size of a study of a domestically developed coronavirus vaccine and to stop the enrollment of volunteers.

The decision comes a week after developers said enrollment of study volunteers has slowed since Russia began giving out the Sputnik V vaccine while the late-stage study was still continuing. They also cited ethical concerns about giving a dummy shot to some of the volunteers. The study size was cut 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 that many of those who received dummy shots had figured it out and gotten vaccinated.

If large numbers of volunteers in the placebo group drop out, it could affect the results, Svetlana Zavidova, executive director of Russia’s Association of Clinical Trials Organizations, said.

“They simply won't be able to gather (the necessary) statistics," she said.

Russia has been widely criticized for giving Sputnik V regulatory approval in August after the vaccine only had been tested on a few dozen people. Two weeks later, the 40,000-volunteeer study was announced.

Despite warnings to wait for the study's results, Russian authorities started offering it to people in risk groups — such as medical workers and teachers — within weeks of approval.

President Vladimir Putin, who has publicly hailed Sputnik V, ordered the Russian government this month to start a large-scale immunization campaign. By mid-December, over 150,000 people had been vaccinated, according to Gintsburg.