(ATTN: RECASTS lead; UPDATES with more info in paras 3, 6, 9-10)
SEOUL, Nov. 30 (Yonhap) -- The first suspected cases of the omicron variant of COVID-19 have been detected in South Korea, health authorities said Tuesday, as the nation tightened its entry restrictions for the African region to prevent it from spreading into the country.
Health authorities have conducted a genome sequencing test on a couple who recently arrived in South Korea from Nigeria and the couple's acquaintance. They tested positive for COVID-19.
The authorities expected the result to be announced after 9 p.m. Wednesday.
The couple, who were fully vaccinated with the Moderna vaccine, visited Nigeria on Nov. 14-23 and tested positive for COVID-19 last Thursday, according to the Korea Disease Control and Prevention Agency (KDCA).
Tests were under way to establish if they have contracted the omicron variant, the KDCA said.
After contact tracing, one acquaintance and the couple's teenage child were found to be infected with the coronavirus.
The acquaintance was suspected of being infected with the omicron variant in polymerase chain reaction (PCR) tests.
Health authorities have also carried out a whole-genome sequencing test on the acquaintance.
The authorities have been tracing passengers who boarded a flight from Nigeria to Seoul via Ethiopia, which the couple boarded.
Of 81 passengers, 45 arrived in South Korea, and the nationalities of the arrivals are under investigation, the government said.
The government has decided to form a task force to discuss ways of coping with the spread of the omicron variant and stopping the inflow of the variant into the country.
From Sunday, South Korea restricted visa issuance and arrivals from eight African nations, including South Africa, to block the inflow of the new COVID-19 strain, joining a host of nations in imposing travel bans from and to the African region.
The World Health Organization (WHO) has designated the omicron variant, first identified by scientists days ago in South Africa, a "variant of concern."
Although it will take time to assess the level of severity of the new strain, the WHO suggested the omicron variant posed an "increased risk of reinfection."