1. How do you get into the field?
No specific answer. Just look for the job with a title like “data analyst”, and good luck! Normally people start from a common programming language, SAS or R, or minimally some sort of SQL, so they can emphasize their programming skills in the beginning to get into the door. When they are already there, they try to pick up data, then move on to business – whole bunch of room to grow.
For all the rest, refer to LauTu's guidelines.
2. Does one have to have CS background?
Not necessarily. CS background can help (so that coding a part of you), can also block your way (because you only see coding, don't see data and how it relates to business – to put it simple: why it matters?).
However, it's highly advisable that you pick up good computing in general, and at least one programming language. The rest is simple: thinking clearly.
3. Does medical background help at all?
Absolutely! After it's healthcare (and something medical is part of it).
To elaborate, there are three parts in everyday healthcare operation: administrative part; financial part; and clinical part. You see where you fit in?
4. How about Health Information Technology?
That's a foundation. Health IT makes things happen – information flows through in an organized and secure way, so that the whole thing can run. However, that's still only IT, although the information is specific to the healthcare industry. Healthcare data analysis sits on the information – normally backed up by IT people, and data management people, but facing business people particularly operations, policy design, contracting, etc.
0. Thanks
You welcome. My native language is Chinese, if you type Chinese, I'll do the same; if you type English I'll also do the same.