Ta Van Thieng, deputy head of the medical center of Chuong My District in Hanoi, will serve a 10-day suspension after he failed to follow centralized quarantine procedures.

He signed papers permitting a 22-year-old Vietnamese man, who had been repatriated from the U.S. on Dec. 20 and quarantined at a military facility in Chuong My District, to leave the camp and go home.

The man had completed the 14-day quarantine and Thieng mistakenly assumed that he had tested negative twice.

However, he had only tested negative once and was waiting for the second test’s results, which came after he reached home in Quang Ninh Province’s Ha Long Town. The second test results showed he was carrying the novel coronavirus.

The Covid-19 prevention protocol is that those who return from abroad are quarantined for 14 days, during which they must be tested at least twice. They can only be allowed to leave if they test negative both times.

Tran Van Chung, deputy director of Hanoi’s Health Department, said the man was quarantined on Dec. 21 along with 88 others.

Their samples were taken for testing twice by the Hanoi CDC.

In this instance, the first test results were confirmed negative on December 23, and 84 were confirmed negative again on Jan. 3.

However, this did not include results of the remaining five, including the 22-year-old man.

Thieng made the mistake of thinking all 89 had been confirmed negative twice, and because they had all finished their 14-day quarantine, he allowed everyone to leave the facility on Jan. 3.

"Signing the papers for ending mandatory quarantine before the results of the second test arrive is against the rules," said Chung.

On Tuesday evening, the Ha Long man was confirmed as Covid-19 "Patient 1498."

Everyone he came into contact with, including his roommates at the quarantine camp and those he met after he left the camp has been tracked down for isolation and testing.

Explaining the delayed results of the five people in the group of 89, Chung said the Hanoi CDC had applied the pool testing method, in which five different samples are pooled into one for testing. In case the pool tests positive, each of the five are tested separately later.

This approach has been applied for months in Vietnam to help screen a large amount of people in a short period of time, he said.