This also marks the 32nd straight day Vietnam has been clear of community transmission.
Among the total, 180 are imported cases which were quarantined upon their arrival in the country.
Up to 260 patients or 81% have recovered from the coronavirus disease, and there have been no deaths.
Two of the 60 remainders still under treatment have tested negative once for SARS-CoV-2, the virus that causes COVID-19, and 12 others negative at least twice.
There are 10,692 people kept in quarantine at present, including 293 at hospitals, 8,631 at other quarantine facilities, and 2,038 at home.
The national steering committee requested people to continue implementing disease prevention and control measures in the new context. Meanwhile, the World Health Organisation (WHO) said the pandemic is still developing complicatedly around the world, recommending Vietnam enhance long-term pandemic control measures.
Earlier on May 17 evening, Vietnam reported two new COVID-19 cases who are Vietnamese people returning from Russia. Both were immediately quarantined upon their arrival at Van Don International Airport in northern Quang Ninh province.
Patient 319, 26 years old, is being treated at the Hanoi-based National Hospital for Tropical Diseases No. 2. Meanwhile, Patient 320, 29 years old, is under treatment at the General Hospital of Thai Binh province.