Fifteen of the 18 new patients (2330-2347), are close contacts of confirmed cases, and three others were detected through screening processes either within the community, locked down areas or at medical centers.

Further contact tracing is underway. The patients are being treated at Hai Duong hospitals.

Twenty-five recoveries were also announced Thursday.

Over 145,000 are quarantined in hospitals, centralized quarantine zones, at home or other designated accommodations.

Since a new Covid-19 outbreak was detected on January 28, it has spread to 13 cities and provinces. The biggest hotspot is Hai Duong Province with 575 cases, followed by Quang Ninh with 60, HCMC with 36 and Hanoi 35.

Hai Duong imposed 15-day social distancing across the province since Tuesday, but has been urged to extend the period given rising cases.