If the body's immune system cannot fight off infection, a number of things could happen but you have to remember that it also depends on what the immune system is trying to fight off. Normally if your immune system is not strong enough to fight off an infection or virus, you will have side affects and will begin to become ill. Side affects could be as easy as a cold to something more severe such as the flu, pneumonia or as its going on right now, the corona virus.
