The Russian vaccination hasn't gone through 'Phase 3' trials. This is the step where you get a large group of volunteers and give them all injections. Some get the real vaccine, others get a placebo. Neither the nurse/doctor administering nor the patent know which is being given (obviously those running the study know). Then keep track of how many people get the disease in each group and whether there are any side effects. If the vaccine works, you'll have far fewer instances of disease in the vaccine group. This is the only way to know that something safely works. Posted By Ghost