On Friday, community workers in Laoshan Community in West Beijing's Shijingshan district conduct a range of measures like disinfection, checking temperatures and setting up smart monitors to ensure residents' safety as China's capital faces increasing pressure of imported cases from abroad and returnees from other parts of China. (Photo: Li Hao/GT)

Beijing reported a new imported COVID-19 case on Tuesday, who was confirmed two days after leaving the centralized quarantine center, which showed very few infection patients may have a longer incubation period posing new challenges to the disease prevention and control, a Beijing Center for Diseases Control and Prevention official said Wednesday.

The man, a student who studied at Miami, the US, departed the city on March 22 and arrived in Beijing on March 24 after stopovers at San Francisco and Hong Kong, according to Beijing's routine press conference on COVID-19 prevention and control on Wednesday. 

The man reported a nasitis history and mild cough upon arrival and was transferred to a designated hospital for checkup. He was tested twice at the hospital and showed negative nucleic acid results. 

The man was discharged from hospital and sent to a centralized quarantine center on March 28 and was transferred to another medical observation center two days later after his co-passenger was confirmed to have contracted the coronavirus. 

The man left the observation center on April 8 after another test showing a negative result and lived with his family. He stayed in a separate room and dined alone without going outside.  

The patient later showed fever, sore throat, and decreasing appetite, which are COVID-19 symptoms. The situation did not ease after he took antibiotics and cold pills. 

The patient went to a fever clinic on April 13 and tested positive for the virus. He was reported as a confirmed infection after taking travel history, CT result, blood tests and other factors into consideration. 

Pang Xinghuo, an official from Beijing CDC, noted that understanding of the new virus requires constant exploration. 

Some patients could have their COVID-19 symptoms covered by other chronic diseases or have a long incubation period. Some may not show noticeable symptoms or positive test results until the late stage of infection, which pose new challenges to the pandemic prevention and control, Pang said. 

Beijing has been reporting sporadic imported cases recently with one from Thailand on Friday before the Tuesday's new infection. The city has so far reported 174 imported cases, with 91 already recovered. 

Global Times