In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

13.07.2020#6285610

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

13.07.2020#6285609

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

13.07.2020#6285608

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

13.07.2020#6285607

In this handout photo released by the Russian Defence Ministry, medical workers wearing protective gear conduct daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

13.07.2020#6285606

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

13.07.2020#6285604

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

13.07.2020#6285602

In this handout photo released by the Russian Defence Ministry, a participant in a coronavirus vaccine trial tests is pictured at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

10.07.2020#6283725

In this handout photo released by the Russian Defence Ministry, a participant in a coronavirus vaccine trial tests is pictured at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

10.07.2020#6283724

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

10.07.2020#6283722

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

10.07.2020#6283720

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

10.07.2020#6283719

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

10.07.2020#6283718

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

10.07.2020#6283717

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

10.07.2020#6283716

In this handout photo released by the Russian Defence Ministry, a medical worker wearing protective gear conducts daily rounds with a participant in a coronavirus vaccine trial during tests at the Burdenko Main Military Clinical Hospital in Moscow, Russia. Editorial use only, no archive, no commercial use.

10.07.2020#6283654