If you do not eat off of carts, if you wash your hands thoroughly before touching food, and if you maintain the modicum of standards of personal cleanliness that one would expect, then the very major Chinese cities are probably just on the same level as their Western counterparts.  I will never eat off a cart and I am very careful in which restaurants I do eat, but no excesssively so.

Considering that you are in China, and hepatitis is very common here, I will say that it is a must to keep your vacination up to date.  I do, but it will be up to you.  I will be very careful of what and where you eat, and what you touch with your hands, even if you clean them often.

but is the locally available vaccine the real one, or just a placebo? view the population of china, the government might just use a placebo, because of its cheap production, unlike the real one which is expensive...

Bigkrishna, your point is a valid point as a matter of fact.  If you wish to assure yourself that you will be given the true vaccine, then please avail yourself of the Gastroenteroloy Department at the No. 1 People's Hospital in Changchun.  Any Changchuner (or whatever they are called in English) will be able to direct you to the hospital.  The hospital fee is inexpensive and you will be given a prescription for the vaccine that will be filled with truly I believe a quality medicine at the No. 1 People's Hospital Pharmacy, located not far from the Emergency Entrance.  That vaccine will be costly, for sure, based upon experience, but it should be effective.