Vietnamese tourists wishing to visit the island are required to fill out health declarations.

The move followed nine foreigners, including seven British, one Mexican and one Irish testing Covid-19 positive in Vietnam as confirmed by the Ministry of Health Sunday. The country has recorded 14 infection cases since Friday after going 22 days with no new infection.

On Sunday, over 200 Vietnamese and four foreign tourists, including two Americans, one from Canada and one from Italy, were on the island. They left on Monday following the central province's decision.

The recent number of visitors to the island only hit 150 to 200 a day, compared to 1,500 to 3,000 during this time in previous years, official data shows.

Ly Son is 30 km from the shore and has an area of nearly 10 square kilometers. Formed by five mountains, four of which are dormant volcanoes, it is a combination of three islands including Dao Lon (Big Island), Dao Be (Small Island) and Mu Cu Islet.

The island district, which used to be off the beaten tourism track, has become increasingly popular among both domestic and foreign visitors in recent years.

Last year, Ly Son received over 230,000 tourists, a 30 percent year-on-year increase, raking in VND276 billion ($12 million) in tourism revenues.

The latest confirmed Covid-19 case in Vietnam is a 66-year-old British woman who has been quarantined in the central town of Hue since Saturday. She is in stable health with no fever or cough.

Earlier, eight foreigners were confirmed to have contracted the coronavirus. They were touring Vietnam when they were tracked down by local authorities on being informed that they were passengers on the same flight as Nguyen Hong Nhung, who tested Covid-19 positive Friday.

Four were intercepted in Quang Ninh Province, two in Lao Cai Province in northern Vietnam and two in the central city of Da Nang, which neighbors Quang Ngai, home to Ly Son Island.

The Covid-19 outbreak has thus far spread to 104 countries and territories around the world, with the death toll climbing to 3,806.