The human immune system's "memory' -- the rate at which it continues to protect us from invading organisms -- lasts much longer than many scientists previously though, according to a new study.

In fact, the researchers states that in some cases, the effects from the immune system can last more than 200 years. That length of time ought to protect anybody for as long as they need, right?

This study shows yet another reason the human machine is so remarkable. The question is if newer medicine and technology will mean 200-year lifespans in the future.