The woman fell after visiting the restroom on the plane, which had been flying at an altitude of 33,000 feet (about 10,000 meters) after departing San Francisco on Wednesday, Vietnam's Foreign Ministry stated Thursday.
Crew members immediately applied first aid and called on some doctors onboard for support. However, all efforts proved in vain and the passenger died before the aircraft landed at Van Don International Airport in northern Quang Ninh Province on Thursday.
The flight captain has since passed on information concerning the incident to aviation and health authorities to carry out all necessary procedures in transferring the deceased.
No specific cause of death has been given.
This was the fifth repatriation flight to carry home Vietnamese citizens stranded in the U.S. due to the Covid-19 pandemic. Passengers included children aged below 18, the elderly, pregnant women, the sick, workers whose visas and labor contracts had expired, and students without residence permits due to dormitory closures.
Previously, 1,700 Vietnamese returned home from the U.S. on repatriation flights operated by Vietnam Airlines.
Vietnam has recorded 381 cases of Covid-19 so far, including eight Russian experts who arrived on July 11. Of the 381, 25 are active cases. The country has not reported any community transmission for three months.
The U.S. has recorded 3.6 million infections and 140,140 deaths, making it the world's biggest Covid-19 hotspot.