How?

What would the AI do that mutating viruses, which try every possible viable combination on their own --- eventually, can't?

Everything is trying to kill humans constantly. There are around 200 epidemic events or so per year that could turn into pandemics, https://centerforhealthsecurity.org/our-work/tabletop-exerci...

You just live with the risk and do your best to use our technology to alleviate suffering. This tool can help with that at some point. But I'm yet to hear what an AI will leap to that nature in tooth-and-claw hasn't? And how?

More importantly how would it know it succeeded? What data from what lab from what animal from what result? This is biology, if you sneeze wrong at an instrument it gives you a different number, see: https://news.ycombinator.com/item?id=49620521