Isn't stress known to reduce body's healing processes. Stress, lack of sleep and proper rest. If you believe something is taking care of you, you will have reduced stress, sleep and rest better. Wouldn't it be logical to expect faster healing. Also human bodies can heal naturally as well.
Stress increases cortisol and cortisol for a long time wrecks the immune system. There are a lot of other things that effect cortisol levels, but it's at least on very plausible pathway for some getting sick more easily.
