A new, more contagious variant of the coronavirus has also surfaced in China.
According to authorities, the first patient is a 23-year-old woman from Shanghai, who has been in the United Kingdom.
The new virus variant, known as B.1.1.7, was first identified in Great Britain and is much more contagious.
The Chinese patient had mild symptoms when she returned to her home country on December 14. Then she ended up in the hospital.
As a precaution, the authorities decided to investigate samples taken from the woman, partly because she has been to the United Kingdom.
China has halted direct flights to and from that country on December 24 to prevent the spread of the new virus variant. Dozens of other countries took similar measures.