He is not able to spread the disease to others, it stressed.

The 21-year-old had his Covid-19 results return nagative again Tuesday morning following a PCR test conducted by the National Hospital for Tropical Diseases in Hanoi, the Department of Preventative Medicine under the Ministry of Health said.

This was the patient's third negative result in a row in the past two days, all determined via PCR screening.

He is still under monitoring and continues to have his samples collected for testing by the National Institute of Hygiene and Epidemiology. In addition to PCR tests, it would also conduct antibody determination screening.

Blood samples of over 50 people that came in close contact with the man have returned negative. They continue to be quarantined as per health ministry protocol.

The man had returned to Vietnam from Russia on August 10, tested positive for the virus on August 25, and was admitted to hospital. After discharge in mid-September, he isolated himself at home for two weeks.

On November 7, the man visited Transport Hospital in Hanoi with a fever and was given medicine for a viral infection.

On November 14, he suffered a 39-degree fever and fatigue. He returned to the hospital and had a novel coronavirus test done, his results returning positive.

Nguyen Trung Cap, deputy director of the National Hospital for Tropical Diseases, said the man could relapse or show false Covid-19 positive results.

"The probability of the man showing false Covid-19 positive results was very low but it can still happen," Cap said.

Earlier, Vietnam had recorded dozens of relapse cases with none bearing the risk of spreading the virus.

Vietnam has reported 1,283 Covid-19 infections and 35 deaths so far. The nation has gone 74 days without any community transmission of the virus.