 It's still a virus and it's still a virus that you can actually then take and put inside of a human. The thing is, it's just not going to cause the same sort of disease that it would if it were like really virulent and very strong. It's essentially weakened. This is called attenuation. You're kind of like turning down the knob or something, the volume on this virus. It's like you turn down the knob on the human virus and up the knob on the chicken virus.