All the latest cases in Hai Duong are F1 contacts of previously confirmed patients and they had been in quarantine late last month.
Among the patients currently undergoing treatment in the country, 46 have tested negative for the virus at least one, with the majority recording several negative results.
At present, the nation has recorded a total of 2,329 positive COVID-19 cases, with 1,430 community cases, including 737 cases detected since the detection of the third wave on January 27.
The same day, seven more coronavirus patients were released from hospital after making a full recovery from the virus, taking the total number of recoveries to 1,580, while the death toll remains at 35.
More than 145,920 people who came into close contact with COVID-19 patients or entered the country from pandemic-hit regions are now in quarantine throughout the nation.
In Quang Ninh province, the second largest COVID-19 hotspot, tests are being offered on demand to enable people to travel now the Lunar New Year holidays have ended.
Six healthcare facilities located in the northern province began offering the test at a maximum cost of VND734,000, equivalent to US$32, from February 16.
An additional two cases were detected in Quang Ninh on January 28 with the other being found in its neighbour Hai Duong.
Since the detection of the third outbreak, the province has recorded 60 cases, second behind Hai Duong with 557.
Authorities in Quang Ninh have also imposed a 14-day quarantine for people returning from Hai Duong and other places that are have been placed under lockdown or which have implemented social-distancing measures, with individuals paying quarantine costs.
Furthermore, Ho Chi Minh City and other northern localities will also isolate people returning from COVIID-19 hotspots following Tet for a period of 14 days in an effort to prevent the possible spread of the pandemic.
In Ho Chi Minh Cinh, 36 people have since been diagnosed with COVID-19, 35 of them linked to the outbreak at Tan Son Nhat Airport, with the other case linked to Hai Duong.
Both Ho Chi Minh City and Hanoi, now require everyone entering to complete medical declarations. The port city Hai Phong and nearby provinces which neighbour Hai Duong have also imposed a variety of travel restrictions.