No chance that piercing the ear will help prevent GERMS and it is debatable if piercing / scarring / intradermal needles on certain auricular acupuncture points does anything other than causing a transient increase in endogenous endorphin production.
If you are talking about the topic covered in "Anatomy Trains", it is some interesting material that gives illustrates another mechanism by which acupuncture might work...although it needs to be researched.