Hm it depends on your ethical beliefs. I think there are severe ethical and practical objections to vivisection from my viewpoint. Firstly it is wrong to me to inflict suffering on one being for the advantage of another. It could be argued that animals are not like humans and therefore it is OK but if they are not like humans why are we extrapolating the results to humans? If you take the view that animals are different because they are less intelligent, would that make it OK to experiment on people with severe learning difficulties? The point at issue seems to me to be can they suffer and if so can I justify inflicting that suffering. There is a case that an animals suffering may be greater because it does not have the imagination to foresee the end of it's pain.

On practical terms the medical profession is at least split on the value of animal research. For instance guinea pigs die if you give them penicillin whereas dogs are indifferent to strynchnine. Thalidomid was subject to testing and retesting in animals before it was released and after it was suspected of causing damage to human foetuses. It only caused similar defects in one strain of laboratory rat. We may well be throwing away things that would help humans because they damage laboratory animal while letting substance dangerous to humans through.

A lot of research seems to be more about keeping researchers in jobs and drug companies in profit than actually improving health. How many cancer breakthroughs do you read about in the papers. It seems every week there is a major cancer cure - until you read somewhere buried in the article that it works in mice or rats. And that is usually the last you hear of it. The publicity helps to get a research grant, the 'cure' doesn't work in humans but the papers aren't going to print the news in a couple of years when it peters out because there will be another miracle cure in the headlines.

It's not an easy subject and it generates a lot more heat than light.