I don’t think most people would consider prevention a type of preparation. EA-funded biorisk efforts presumably did not consider it that way. And more to the point, I do not want to lump prevention together with preparation because I am making an argument about preparation that is separate from prevention. So it’s not about just semantics, but precision on which efforts did well or poorly.
I think it actually is common to include prevention under the umbrella of pandemic preparedness. for example, here’s the Council on Foreign Relation’s independent committee on Improving Pandemic Preparedness: “Based on the painful lessons of the current pandemic, the Task Force makes recommendations for improving U.S. and global capacities to deliver each of the three fundamentals of pandemic preparedness: prevention, detection, and response. ” Another example: https://www.path.org/articles/building-epidemic-preparedness-worldwide/
So it might be helpful to specify what you’re referring to by preparation.