According to the Kyodo agency, the princess was admitted to the Tokyo University Hospital.
On February 8, she was hospitalized with the coronavirus after she tested positive for COVID-19.
Earlier, Turkish President Recep Tayyip Erdogan said that he and his wife had been diagnosed with the Omicron strain of coronavirus.
According to Johns Hopkins University, the number of cases of COVID-19 in the world has exceeded 400 million.