Animal testing has been an essential part of the development of life saving vaccines and cures for several diseases that were considered Life Threatening before. Although humans and animals aren't exactly the same, there exist certain similarities in our Physiology and DNA that enable scientists to test certain products on animals to predict how the human body will respond or react to the same products. Of course this does not mean that the tests will be a hundred percent accurate, but it means that when ready to test in humans animal testing would have helped eliminate majority of the risks involved with human testing.
Here's a little history on the development of Vaccination:
The Smallpox vaccine was the first vaccine that was used in a large scale to immunize people. And the development of the vaccine could not have been done without Edward Jenner, who noticed a similarity between Cowpox (in cows) and Smallpox(in humans). Although Cows and Humans are completely different species, the introduction of the pus from Cowpox into humans somehow made them Immune to Smallpox. In fact - The word Vaccination is derived from the word 'Vacca' which is Latin for Cow. And the smallpox vaccine was so effective that those of us born after the 1980 don't even need the vaccine because Smallpox was eradicated as a result of widespread immunization.
Louis Pasteur developed the Anthrax vaccine in by testing them on sheep first. If he anthropomorphized the sheep he was supposed to test on, we would be left with no Anthrax Vaccine! Science is about making responsible choices that could be beneficial to many. In my opinion, if the loss of one animal life can save a few human lives, then it is justified. I consider animals important, but if i had the choice between saving a human and saving an animal, I would pick the human over the animal any day.
When we are talking about animal testing in terms of life-saving cures, I believe that the ends essentially justify...