Very, very good. Definitely a 4.5. A thick, satisfying slice of end of the world bio-horror. This covered a wide range of things incorporating emergent AI, religion, current US politics and our dire state of preparedness for pandemics. There were many little human moments written into the chaos and big ideas which, in the end were the main engine driving the story forward. Totally recommended and I can see why it had the word of mouth it had.