Well I have no idea what you mean by that. SARS lasted for less than three years in the early 21st century, infecting just a few thousand people only, and there have been no cases for seventeen years or more. It is effectively extinct in the human population (unless you have a different definition of extinct). Like smallpox, samples of the virus still exist in research laboratories. It doesn't mean that it's impossible for a variant to leap from wild animals. As yet, that hasn't happened and it's been quite a long time. I think that's probably enough to rest my case. Cheers.