How to prevent bioterrorism?

In an age of AGI —> ASI, how do we realistically prevent a catastrophic bio weapon from causing existential threats to humanity?

As hopeful as I am about advanced AI bringing huge benefits to mankind, I really worry about some state actor or maybe even a single individual being able to cause such tremendous harm. Wouldn’t unleashing a novel pathogen (accidentally or deliberately) already lead to a possible extinction event?

What would our recourse be?