Le Thuc Tri, 33, has tested negative for the novel coronavirus three times in a row, Van Cong Minh, health department director in the Mekong Delta province of Vinh Long, said Monday.

After 32 days of treatment, Tri will now be moved to a centralized quarantine zone in the Vinh Long Tuberculosis and Lung Diseases Hospital for the next 14 days, Minh said.

Tri was part of a nine-person group who crossed into Vietnam into the Mekong Delta province of An Giang on December 24. He returned to his house in Vinh Long, but his mother reported him to authorities so he could be quarantined.

Apart from Tri, three others in the group have been confirmed infected with the novel coronavirus.

Earlier this month, Tri was placed under criminal investigation for "spreading dangerous infectious diseases in humans." He is the second person to be placed under such a probe, the first being a Vietnam Airlines' flight attendant who allegedly breached Covid-19 quarantine protocols and infected three others.

Until their cases, people flouting Covid-19 prevention regulations were let off with fines.

Of the 1,548 Covid-19 cases recorded so far in Vietnam, 99 are still active and 35 have died. No community transmission has been recorded nationally in nearly two months.