The human body is always envolving
The human body is always envolving.
To begin with, in my point of view, such tests cannot be run on harmless and helpless animals, when they have nothing to deal with our phisycal condition. Execpt for allergies. In this case vaccines to improve our immune system should be tested on people themselves. Animals are innocent and live in this planet just like we do, so I think, it is wrong to use them to find a solution to our problems.
Secondly, there might be other ways for scientists to improve these medicines, such as: using computer models and programs or even trying to get as much knowlegde from statistics as they can. Especially when computers are more advanced than ever and can do immaginable things.