South Korea has discovered its first cases of COVID-19’s omicron variant, the Korea Disease Control and Prevention Agency said Wednesday evening.

The first cases of the omicron variant were confirmed in a couple in their 40s who recently traveled to Nigeria and a man in his 30s whom they met after returning.

The couple returned to Korea on Nov. 24 after staying in Nigeria from Nov. 14 through 23. Their PCR tests, taken on the day of their arrival, came back positive the next day.

As both were fully vaccinated, they were exempted from post-travel quarantine and had at least a day to roam freely in Incheon, where they live.

The couple’s teenage son also tested positive since. His omicron test results are still pending.

Later the same evening the agency said a further two cases were identified, also among recent travelers to Nigeria, bringing the total number of known cases to five.

The two women in their 50s visited Nigeria from Nov. 13 to 22. They tested positive Nov. 24, a day after returning. Neither were vaccinated.

So far all of the patients confirmed with omicron have shown mild symptoms, the agency said.

The agency said in an emergency announcement Tuesday evening that it was examining the four cases for possible infection with omicron after one of the samples tested positive for “variant that isn’t delta.”

Eight people who have come into contact with the couple are being tested, in addition to the 45 passengers who were aboard the same flight.

The agency is also investigating contacts of Japan’s first omicron infection, a diplomat from Namibia, who arrived at the Japanese capital’s Narita airport after a layover at Incheon Airport in Korea.

On Tuesday the agency and concerned ministries formed a task force dedicated to responding to the new variant.

Korea announced on Saturday it was barring foreign arrivals from eight southern African countries -- South Africa, Botswana, Zimbabwe, Namibia, Lesotho, Eswatini, Mozambique and Malawi -- and that it would be sending samples of all overseas arrivals who tested positive for sequencing as precautionary measures against omicron.

By Kim Arin (arin@heraldcorp.com)