South Korea confirmed on Wednesday that five cases of Omicron were detected in the country and connected to people traveling from Nigeria last week.

The Associated Press reported that two of the cases involving the new variant are linked to women who went to Nigeria and flew back to South Korea on November 23.

The three remaining cases are connected to a couple who traveled from Nigeria to South Korea on November 24, and their friend who picked them up from an airport and drove them home.

The couple was fully vaccinated, but the friend who picked them up and their teenage child was not vaccinated, said Choi Seung-ho, an official with the Korea Disease Control and Prevention Agency (KDCA).

Health care workers said they’re running a genetic sequencing test on the teenager and the relatives of the friend who drove the couple home to see if anyone has been infected with the new variant.

So far the four individuals have not experienced any severe symptoms. They’re reported mild respiratory symptoms and muscle pain, said Park Young-Joon, another KDCA official.

With the arrival of the new Omicron variant, South Korea announced new travel restrictions to go into effect for at least two weeks for all passengers. Everyone arriving from out of the country, regardless of their vaccination or citizenship status, must quarantine for at least 10 days.

Further restrictions include strict quarantine for travelers for ten days including South Korean nationals even if they are fully vaccinated. The country has also reportedly stopped issuing visas for non-nationals from eight African countries.

However, scientists say it’s not yet clear whether the variant is more contagious or dangerous than other strains, including the Delta variant.