LLMs change nothing. The sequences for various viruses are going to be published or leaked whether anyone involved uses LLMs or not. It's a total red herring.
A big value proposition of LLMs is their ability to synthesize and remix. Sure, you can access viral sequences today, but with an LLM you might be able to say "given these covid variants, make me a version as deadly as the first one and as virulent as the latest variant".