I understand your meaning, so you can use it that way -- but it sounds a little strange. "Confine" is usually used in the context of "enclosing / locking up," like a criminal put in prison. It's commonly used figuratively -- so you could also say "right now the disease is confined to the northern region." Ideas and thoughts, however, aren't really something that can be enclosed in a room or an area. You might try "limited to" or "prevalent among" instead.