Vietnam Airlines will strictly follow the direction of the aviation authorities for requiring passengers to wear masks on all domestic and international flights (Cre: VIAGS).  

Check-in service will not be provided to passengers who are not equipped with and wearing masks. Vietnam Airlines also expects passengers to comply by wearing masks throughout the flights.
As previously decided, to uphold its national responsibilities and continue to grant passengers access to Vietnam, starting from March 15th, 2020, Vietnam Airlines will carry passengers meeting all immigration and health requirements back to Vietnam on flights departing from London (the UK), Paris (France), and Frankfurt (Germany).
Passengers should note that the airline will conduct mandatory interviews and body temperature checks to ensure that they are eligible for boarding flights to Vietnam. Passengers must wear masks and gloves throughout the flight. They will also be tended to by way of constant health monitoring during the flight and will be quarantined as per regulations after landing.
The entire flight crew will be equipped with specialized medical protective clothing. To limit the likelihood of infection, in-flight services are provided at a minimum with only drinks and dry snacks offered. These flights will be landed at predetermined airports in Vietnam after the carrier works with competent authorities to come to an official decision.

Nguyen Mai Huong-COMM