This is a theme that is mentioned again and again, and I cannot understand the thought behind how vaccination could damage the immune system. The way I understand it, vaccination uses some of the multiple functions of the human immune system to decrease the risk of infection at future exposure, so I don't see how it could be "damaging". I would like to understand this, and prefer information that comes from reputable, factual sources. Also, I am not really interested in info related to rare, severe reactions such as Guillain-Barre. Thanks!