The four Vietnamese patients include three men and a woman aged between 22-67. They recently returned from Japan, Cambodia, South Korea, and the USA to Ho Chi Minh City and Phu Yen and Tay Ninh provinces.
They were sent to quarantine areas upon arrival and are now being treated at local hospitals and healthcare centres.
With these new infection cases, the number of Covid-19 patients in Vietnam has increased to 2,791, including 910 locally-transmitted cases reported since the new outbreak started in Hai Duong on January 28.
As of 6 pm on April 19, a total of 2,475 Covid-19 patients had recovered and been discharged from hospital. There have been 35 deaths, most of them being the elderly with serious underlying diseases.
At present, over 40,000 people who had close contact with Covid-19 patients or returned from virus-hit areas are being monitored at hospitals, quarantine facilities, and at home.