Sickness Resistance is a career reward trait. Sims will receive this trait when they reach level 8 in the Doctor career. Sims with this trait can perform their jobs without worrying about that one thing that they never could do when they first started. It will also make their life at home easier around situations where this trait could be handy. Sometimes it is also possible to finish their aspirations easier with this trait. When sims lose or quit their job, the Sickness Resistance trait will still be part of the sim's Simology.