The sailor, 40, works for the IPANEMA, a container ship registered in Liberia. The ship left Japan on June 6 and arrived at the Hon Gai Port in Ha Long Town, Quang Ninh Province on June 23.

The man was quarantined on the vessel upon arrival. On July 7, he disembarked and was sent to quarantine at the Van Long Hotel in the northern province.

His first test two days later showed negative but the second test Friday came positive. "Patient 383" has been transferred to the National Hospital for Tropical Diseases in Hanoi for treatment.

With 357 recoveries, Vietnam now has 26 active Covid-19 patients.

By Sunday, the nation has gone 94 days without detecting a single case of Covid-19 infection caused by community transmission. No Covid-19 deaths have been recorded to date.

The novel coronavirus pandemic has killed more than 605,600 worldwide.