Vietnam’s Ministry of Health reported four imported coronavirus cases on Thursday, all quarantined upon arrival.
The four latest patients are Vietnamese returnees from the UAE, the health ministry said.
They arrived at Cam Ranh International Airport in south-central Khanh Hoa Province on board flight VN88 on Tuesday.
They were sent to collective quarantine in Phu Yen Province, around 160km north of Khanh Hoa, upon entry.
They were tested for COVID-19 on Tuesday and the results returned positive on Wednesday.
The four are being isolated for treatment at the Phu Yen General Hospital.
Vietnam has confirmed 1,385 COVID-19 cases as of Thursday night, with 1,225 recoveries and 35 virus-related deaths, according to Ministry of Health data.
The country is quarantining 20,743 people who either had close contact with confirmed patients or made an entry from pathogen-struck regions.
Vietnam began its human trial of a locally made COVID-19 vaccine on Thursday, with 30 volunteers given a shot within the first hour.
Researchers are still recruiting more volunteers, all of whom will be insured against any potential complications.
The jab will be tested over three phases, with the final one to conclude in August next year.
Should tests go as planned, the vaccine will be manufactured and made available for local residents in late 2021 or early 2022, the producer said.
A shot is projected to cost VND120,000 (US$5) if it passes all human trials and is approved for mass injection.