Timing, page-5

Yes you are right about the size of the population in Belarus. And if you are also right with your statement, Russia controls and influences a lot of activity in and around Ukraine, open the link annexed below.

7 common concerns about clinical trials in Eastern Europe

From this it says:

It is noteworthy that Eastern Europe, Russia and Ukraine have attracted a number of FDA and EMA inspections during global clinical trials. Yet many of these audits show the same if not better results in Russian sites than those in the US or Western European countries. Russian research sites often demonstrate a high adherence to ethical standards. They provide adequate ICFs, an appropriate monetary compensation for volunteers, full accuracy of records and strict adherence to initial investigation plans.

This is also still a common apprehension that Eastern Europe and Russia are behind in the development and application of the latest procedures and technology. This is not the case.