However, results later showed she'd tested negative, officials said.

Vietnam Airlines flight N50, which took off from London's Heathrow Airport to Saigon's Tan Son Nhat Airport, had flown for two hours when the HCMC International Health Quarantine Center received news that a Vietnamese female student on the flight had coughed and found to be feverish. She could be carrying the Covid-19 virus, the center was informed.

The student had already exhibited symptoms back in the U.K. and had herself checked up. She was diagnosed as having a flu and not tested for the Covid-19 virus, her family said.

Upon receiving the news, crew members on the flight transferred the girl to the back seat and separated her from other passengers. After landing in Tan Son Nhat at 5 a.m., she was taken to the HCMC Hospital of Tropical Diseases for Covid-19 tests. All passengers and crew members on the flight, around 100 people, were also quarantined in Cu Chi District. The Vietnam Airlines plane was disinfected after the incident.

Nguyen Huu Hung, deputy director of the HCMC Department of Health, said late on Thursday the girl has tested negative for the Covid-19 virus and her co-passengers and the crew would be removed from quarantine.

As of Thursday morning, HCMC had isolated 394 people in several quarantine zones in the city, and 594 in their own homes. The city is treating one Covid-19 patient.

Vietnam has recorded 44 Covid-19 cases so far, including nine people in the central province of Binh Thuan, five in Hanoi, and other cases in Lao Cai, Ninh Binh and Quang Ninh in northern Vietnam; Da Nang, Thua Thien-Hue and Quang Nam in central Vietnam.

The highly infectious novel coronavirus has thus far spread to 125 countries and territories around the world, killing more than 4,700 people.