okay hab schon was gefunden. Auf einer Website heißt es in der englischen Version "certified prevention assistent". Falls jemandem aber noch was anderes einfällt, bitte melden! :)

Ist mE ohne Erklärung weder auf Deutsch noch auf Englisch verständlich, also einfach erklären.

It may sound riduculous to you, but if you try googling the suggested title with the additional word "certificate", you'll find a large number of correspondingly named qualifications on offer from various universities.

"Certified prevention assistent" will confuse and/or amuse ...

Especially as the word is spelled "assistant" ;-)

Incidentally, if I put "Child and Adolescent Health Care Professional" into Google , I get precisely three hits ...

"Child and adolescent health care professional" would cover all sorts of medical professionals, including paediatricians, child psychiatrists and psychologists, paediatric nurses, and medical assistants ...

"Präventionsassistentin" is a medical assistant with an additional qualification.

It seems to apply to other fields as well as paediatrics,
http://www.eusana.de/index.php?artid=2916&mod...
but in the context of child and adolescent health care it would be a p(a)ediatric medical assistant 
http://www.ehow.com/list_6142102_duties-pedia...
with a certificate in health promotion and disease prevention.
I am not aware of a more elegant description.