Nigeria on Wednesday confirmed its first cases of Omicron COVID-19 variant in air passenger arrivals but amended an earlier statement to say the travellers had arrived in Nigeria only over the past week.

Initially, the Nigeria Centre for Disease Control (NCDC) said that retrospective sequencing of previously confirmed COVID cases among travellers to Nigeria had identified the Omicron variant among a sample collected in October.

An amended statement from the NCDC did not mention the October sample and a spokesperson said that sample contained the Delta variant, not Omicron. First reported in Southern Africa a week ago, Omicron has highlighted the disparity between massive vaccination programs in rich nations and sparse inoculation in the developing world.

The NCDC said Omicron was detected in “three persons with a history of travel to South Africa“. “Given the highly likely increased transmissibility of the Omicron variant, it is imperative to put in place measures to curb community transmission,” the NCDC said.

Following a meeting on Wednesday with Nigerian President Muhammadu Buhari in Abuja, South African President Cyril Ramaphosa slammed travel restrictions as “harsh and unfair” and said the economic damage would be “considerable and long lasting.

“Several nations have imposed travel curbs on countries in Southern Africa, while Hong Kong and Canada have barred non-resident travellers from Nigeria. South Korea said it detected the Omicron variant in fully vaccinated travellers who arrived last week from Nigeria.

Data from other countries indicates the variant was circulating before it was officially identified in Southern Africa and has since been detected in more than a dozen countries. Work to establish if it is more infectious, deadly or evades vaccines will take weeks.