One difficulty with testing the ebola vaccine compared to polio is that enough people were catching polio that you could do a double blind test giving some people vaccine and some a placebo and then compare infection rates between the groups. Since ebola is deadly, but not very common (even in Africa) it would be difficult to get a statistically meaningful test without actually intentionally infecting both the test and control groups to see if there is a difference in infection rates. Without that, ebola is going to go from the petri dish to general human use without a wide scale effectiveness test.
Thousands of school children were the field test for the polio vaccine.