A flight carrying German business travelers from Frankfurt, jointly arranged by German Chamber of Commerce in China, German diplomatic missions, and Lufthansa airlines, landed in Tianjin at 11:45 am on Saturday. Photo: Courtesy of Lufthansa Group

A passenger on LH342, the first chartered flight from Germany to China carrying up to 200 German passengers, tested positive for coronavirus after arriving in North China's Tianjin although he did not show any symptoms. 

Industry insiders said that the case will not cast shadows on the opening of more chartered flights and the so-called "fast track" channels between China and some foreign countries. But more strict prevention and quarantine measures are likely to be phased in to prevent more imported cases, as China is now going full speed to restart the economy.

The asymptomatic infected passenger is a 34-year-old male engineer from Blaustein, Germany, according to information released by the Tianjin health authority on Sunday. He took flight LH342 from Frankfurt and arrived in Tianjin at noon on Sunday. After testing positive for the coronavirus, he was transferred to a local hospital for medical observation. 

LH342 was the first chartered flight to bring German managers, workers and family members back to China. The flight was jointly arranged by the German Chamber of Commerce, German diplomatic missions in China, and Lufthansa. 

A passenger on the flight revealed on hisTwitter that they had been required to be quarantined for two weeks. 

"Our luggage was disinfected and we were brought into our rooms, which we cannot leave for two weeks. A notice on the table told us to expect additional health checks," one person who claimed he was on the flight from Frankfurt to Tianjin posted on Twitter.

The Twitter user said online that before departure, passengers had to take a nucleic acid test for the coronavirus once, and upon arrival, there was a second test for both the virus and for antibodies. 

The second chartered flight from Germany with some 200 business travelers is scheduled to arrive in Shanghai on Thursday, Lufthansa told the Global Times. 

It is not clear whether that flight will operate as scheduled. The carrier declined to make further comment when contacted by the Global Times on Sunday. 

Jens Hildebrandt, executive director of the German Chamber of Commerce in China, told the Global Times in an earlier interview that passengers who took the flight had to take nuclei acid tests in Germany before boarding. There were also certain security measures on the flight, and a 48-hour quarantine upon arrival. 

It is normal to see different nuclei acid test results in Germany and China as the primer designs of the test kits may be different in the two countries and a confirmed passenger might be an asymptomatic carrier of the virus, Yang Zhanqiu, a deputy director of the pathogen biology department at Wuhan University, told the Global Times on Sunday. 

"It is highly possible that the primer designs of the test kits are different in the two countries, hence, will show different results," Yang said, adding it is also possible that the virus did not show up during the person's journey on the flight. 

A 14-day quarantine is enough for the rest of the passengers on the same flight as the average incubation period of COVID-19 is five to six days, according to Yang. 

"The case will not affect China's loosening on controls of foreign business personnel to come back to their workplaces in China, because our epidemic control and prevention work has become very sophisticated and strict," Yang said.