Please do take precautionary protection measures like any other flu, such as wearing a mask if you have a cough and washing your hands.
Foreign nationals who have visited Hubei and Zhejiang Provinces within 14 days of arrival in Japan (effective from 0:00AM Feb 13 JST), or who have a Chinese passport issued by these provinces, will not be able to land in Japan except under special circumstances for the time being.
Medical expenses may be high in the event that you become sick or injured and require a visit to the hospital whilst in Japan so please do not forget to take out the necessary travel insurance.
For further information on hospitals and insurance, please visit the links below.