Jet engines are designed to contain a fan blade failure, and the engines and airplanes are designed with this type of failure in mind. This is more critical in the modern high-bypass designs with large fans. Pictures from bird strikes sometimes show pretty severe damage, but I don't remember any that actually lost a fan blade.
How often does a jet engine actually lose a fan blade?
This is different from a rotor burst, which is uncontained (like with Qantas Flight 32).