True Health

Notice is does not say anything about "feeling" sick or not sick.
It does not say anything about your lab tests levels being in the normal range as being healthy (i.e. blood pressure, cholesterol, blood count, etc.)
It does not say that because you do not have a disease, that you are healthy.
    
Health is a balancing point between mind, body and spirit.  Our bodies are in a constant state of homeostasis.  As we do more things that improve our health we move closer to a state of health.  As we do more things that are not good for our bodies we slide further from health.

True health can be having a fever, it can vomiting, it can be coughing, etc.  Those can all be very normal for a healthy body to do.  If your body is fighting an infection, raising the body temperature, (fever) can help fight the bacteria faster.