Zambia has detected its first cases of the Omicron coronavirus variant in three people who tested positive for COVID-19 in the past week, the health ministry said on Saturday.

The three cases are a man living in the district around the capital Lusaka who travelled abroad recently and is showing mild symptoms, a man in Chibombo District who also travelled abroad recently but is asymptomatic, and a woman in Lusaka District who had not travelled abroad recently and had mild symptoms.

The Omicron variant first detected in southern Africa last month has caused global alarm, with countries imposing travel restrictions for fear it could spread quickly even among vaccinated people.

Scientists are trying to establish whether Omicron – labelled a “variant of concern” by the World Health Organisation – is more contagious or resistant to existing vaccines.