Flight VN524, operated by an Airbus A350 carrying nearly 250 passengers, was diverted after a Vietnamese passenger developed health problems while on board.
Cabin crew provided first aid and medical assistance in line with emergency procedures, but the passenger's condition did not improve, prompting the flight crew to divert to Hong Kong for urgent medical treatment.
According to the airline, ground staff in Hong Kong coordinated with airport authorities to prepare an ambulance, medical personnel and other support services before the aircraft landed at 10.59 am local time.
The passenger was transferred to a nearby medical facility for further treatment after landing.
The flight later resumed its journey to Shanghai, departing Hong Kong at 12.10 pm local time.
Vietnam Airlines said the decision to divert was made in accordance with operational and flight safety procedures, with priority given to ensuring the passenger received timely medical care.
The airline noted that it had previously diverted flights to destinations including Kolkata, Istanbul, Danang and Hue to assist passengers requiring urgent medical attention.