Raw oysters "got me" twice in Qingdao of all places. Premium seaside restaurant and hosted by a local real estate tycoon on both occasions. From my limited experience, the safest locations for seafood seem to be heavily Japanese and Korean influenced cities like Dalian and Weihai where quality norms are unusually high.

In Shanghai and environs would only eat raw fish and seafood if the chef is Japanese or Korean. On occasion have also brought my own fish, Korean style, to a Japanese friends restaurant in the Shanghai area and have the chef prepare it in different ways.