Photo/Illutration An electron microscope image of the novel coronavirus (Provided by the U.S. National Institute of Allergy and Infectious Diseases)

Health officials have confirmed that a Tokyo woman in her 50s contracted the mutated strain of the novel coronavirus, the government announced on Dec. 27.

The Tokyo resident's flight from Britain landed at Haneda Airport on Dec. 13 and she appeared to be healthy on arrival, according to the health ministry.

She is now the eighth person who has tested positive for the new coronavirus variant in Japan.

She tested negative at first during the quarantine processing at the airport, according to the ministry. But then on Dec. 19 she ran a slight fever and experienced pain in her throat. She has been hospitalized since Dec. 22.

The National Institute of Infectious Diseases (NIID) ran an analysis and detected the new variant of the virus.

After she returned to Japan, she stayed in an accommodation facility and did not use public transportation, officials said. It is believed that she has not been in close contact with anyone.

The new variant is believed to be more contagious than the novel coronavirus responsible for the pandemic.

Nineteen countries and regions have confirmed cases of it to date, according to the NIID.