Zombitosis
The vaccine to becoming a zombie. One receives this vaccine by contracting mono. You become dead, but only slightly. On recovering you will no longer be able to become a zombie. One future career choice could now be zombie hunter.
"Wow! You look so dead! Are you sure you're not a zombie?"
"No, it's ok, I have zombitosis, so I'm immune."
"No, it's ok, I have zombitosis, so I'm immune."