We Canadians were told we should have the Japanese Encephailitis injection on arrival in Korea but it is not a common disease now. People did die in the past. I didn't get the vaccine. This encephalitis is carried by mosquitos so if you take precautions like mosquito netting, and avoid bites, you will prob. be ok. Same goes for rabies. We were advised to take malaria pills before going to Indonesia Bali but later found the drugs were making us sick. The doctor in Indonesia told us to stop taking them. I'd be more concerned about water (nasty E.coli strains) and hepatitis in China. Some people bring their own sterile needles too.
Use a money belt when travelling and put your valuables (passport, tickets, credit cards, extra cash) in a bank safety deposit box when you arrive in a city (ask about holidays and closed dates). I don't use hotel safe boxes. Do not bring valuables to a beach when you swim. Leave all good jewelry at home.