Recovered patients with severe novel coronavirus pneumonia (NCP) pose for photos with medical staff at the west campus of Wuhan Union Hospital in Wuhan, central China's Hubei Province, Feb. 19, 2020. A total of 31 patients infected with severe NCP recovered and were discharged on Wednesday from the west campus of Wuhan Union Hospital, after receiving medical treatment of nearly two weeks. (Xinhua/Chen Yehua)

Aerial photo taken on Feb. 19, 2020 shows a sea-rail intermodal freight train waiting for departure at the Zhengzhou terminal of China Railway Intermodal in Zhengzhou, central China's Henan Province. The sea-rail intermodal freight train, loaded with 35 sets of containers, left from Zhengzhou terminal of China Railway Intermodal in Henan to Qingdao port of Shandong on Wednesday, making the restoration of its regular operation after the Chinese Spring Festival of 2020. (Xinhua/Li An)

A taxi leaves with passengers who have disembarked from the "Diamond Princess", a cruise ship which has been kept in quarantine at the port of Yokohama in Japan, Feb. 19, 2020. Passengers on the novel coronavirus-inflicted Diamond Princess cruise ship started disembarking on Wednesday in Japan's Yokohama Port after a two-week quarantine period. In at least three days, nearly 3,000 people will disembark from the ship which has 542 confirmed cases of the pneumonia-causing virus so far, according to the government. The first group of about 500 mainly elderly passengers who have tested negative for the virus started to get off the ship after finishing final checkups with doctors. (Xinhua/Du Xiaoyi)

Ms Yan bows to express gratitude to medical workers when leaving hospital after recovery from novel coronavirus pneumonia (NCP) at a hospital in Wuhan, central China's Hubei Province, Feb. 18, 2020. On the day of her birthday, Yan was discharged from hospital after recovery. (Xinhua/Wang Yuguo)

Xinhua News Agency journalists Wang Yuguo (L) and Xu Yang prerpare to enter isolation wards of a branch of Tongji Hospital in Wuhan, central China's Hubei Province, Feb. 18, 2020. The journalists with Xinhua News Agancy have been busy on the frontline in Hubei Province recording the people's war against the novel coronavirus disease (COVID-19) there. (Xinhua)

The Azadi Tower is illuminated in Tehran, Iran, on Feb. 18, 2020, to show support to the epidemic-hit city of Wuhan in central China. The Azadi Tower, a landmark monument in the Iranian capital of Tehran, was lit up here on Tuesday night, as part of a ceremony showing support for China in the face of the novel coronavirus outbreak. (Photo by Ahmad Halabisaz/Xinhua)

Aerial photo taken on Feb. 19, 2020 shows villagers sowing seedlings of the herbs for Chinese medicine through the seeding machines at Tongying Village of Bozhou, east China's Anhui Province. Villagers across China have been busy with agricultural production as temperature rises. (Photo by Zhang Yanlin/Xinhua)

Medical worker Li Zuofan cheers up for himself at an intensive care ward of the novel coronavirus infection cases at a branch of Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology in Wuhan, central China's Hubei Province, Feb. 18, 2020. Li Zuofan, 39, is a doctor working at the anesthesiology department in the Tongji Hospital. He got infected with the novel coronavirus (COVID-19) when performing an operation with a novel coronavirus infection case. Through treatment, Li has recovered a lot and hoped to return to his duty after recovery as soon as possible. (Xinhua/Wang Yuguo)

Former South Korean President Lee Myung-bak (front) arrives at the Seoul High Court in Seoul, South Korea, Feb. 19, 2020. A South Korean appellate court on Wednesday sentenced former President Lee Myung-bak to 17 years in jail over a set of corruptions, including bribery and embezzlement. The Seoul High Court handed down the ruling on Lee, who served as the country's head of state for five years from early 2008, fining him 13 billion won (10.9 million U.S. dollars). (NEWSIS/Handout via Xinhua)

German Chancellor Angela Merkel (R) and visiting Finnish Prime Minister Sanna Marin attend a joint press conference at the German Chancellery in Berlin, capital of Germany, Feb. 19, 2020. (Xinhua/Shan Yuqi)

Turkish President Recep Tayyip Erdogan delivers a speech at the parliament in Ankara, Turkey, on Feb. 19, 2020. Turkish President Recep Tayyip Erdogan on Wednesday vowed to launch an operation into the Idlib province of Syria if the Syrian government does not retreat by the end of February. (Photo by Mustafa Kaya/Xinhua)

Staff members work at the assemble plant of FAW-Volkswagen Automobile in Chengdu, southwest China's Sichuan Province, Feb. 19, 2020. FAW-Volkswagen Automobile Co., Ltd. resumed production at its four production bases across China as of Monday amid the novel coronavirus (COVID-19) outbreak. (Xinhua/Liu Kun)

Four new technology experiment satellites are launched by a Long March-2D carrier rocket from the Xichang Satellite Launch Center in southwest China's Sichuan Province, Feb. 20, 2020. China sent four new technology experiment satellites into planned orbit from the Xichang Satellite Launch Center Thursday. (Photo by Jiao Huangxin/Xinhua)

Mr. Wang, 36, a recovered coronavirus patient, "hugs" medical staff without body contact before leaving Leishenshan (Thunder God Mountain) Hospital in Wuhan, capital of central China's Hubei Province, Feb. 18, 2020. Leishenshan Hospital, a makeshift hospital built in Wuhan amid the novel coronavirus disease (COVID-19), Tuesday saw its first two cured patients, including Wang and an 83-year-old woman patient. (Photo by Gao Xiang/Xinhua)

Kenyan primary school students hold placards to support China in Nairobi, capital of Kenya, Feb. 19, 2020. Many children from across the world have created their paintings in solidarity with China's fight against novel coronavirus epidemic. (Xinhua/Li Yan)