ABSTRACT
Objective To understand the epidemiological characteristics and laboratory test results of COVID-19 infections among passengers in an inbound flight to Beijing, and to provide reference for the management of imported COVID-19 cases. Methods Flight information, centralized quarantine sites, transfer vehicle, laboratory test results, clinical progression and outcome and other information of all passengers in an inbound flight to Beijing on August 6, 2021 were collected and analyzed. Results A total of 15 passengers were COVID-19 positive. They were all tested negative for nucleic acid 48 h before boarding. The earliest positive was on the day of entry, and the longest was on the 13th day of entry, with the median of being the 3rd day after entry. There were inconsistent nucleic acid test results of 8 positive passengers reported by two institutions and the CT values were close to cutoff. The initial serum antibody levels were higher than 100（s/co） in 6 positive passengers. Nobody was infected during transportation and quarantine. Conclusions Nucleic acid testing before boarding the flight should be able to identify majority of positive cases. Accordingly, joint screening strategy such as blood serum antibody test for inbound passengers with suspicious preliminary screening results of COVID-19 should be implemented to determine the infection history of the case.