Top executives at companies including aluminum giant United Co. Rusal, as well as billionaire tycoons and government officials began getting shots developed by the state-run Gamaleya Institute in Moscow as early as April, the people said. They declined to be identified as the information isn’t public.

The Gamaleya vaccine, financed by the state-run Russian Direct Investment Fund and backed by the Defense Ministry, last week completed a phase 1 trial involving military personnel. The institute hasn’t published results for the study, which involved about 40 people, but has begun the next stage of testing with a larger group.

Gamaleya’s press office couldn’t be reached immediately for comment. Kremlin spokesman Dmitry Peskov, who recovered from Covid-19 after being hospitalized with the virus in May, said he doesn’t know the names of anyone who’s received the institute’s vaccine.