2,000 people, most of them children have been placed into quarantine after two cases of the Omicron variant were detected at an international school in the Swiss cantons of Geneva and Vaud.

Geneva, a hub for international diplomats and home to the World Health Organization (WHO) which last week classified Omicron as a SARS-CoV-2 “variant of concern”, had previously confirmed one case in an individual who had returned from South Africa and another suspected case linked to the same individual.

“Following two confirmed cases of the Omicron variant which attended the Châtaigneraie campus of the International School of Geneva this week, the cantonal medical services of the cantons of Vaud and Geneva have jointly decided to quarantine all of the students and campus staff for ten days,” Geneva health authorities said in a statement late on Thursday (Dec 2).

Switzerland has identified a handful of cases of the new variant spread across five cantons and imposed travel bans from southern Africa and quarantine requirements on arrivals from 23 countries including Japan, Britain, and Canada.

Authorities said 1,600 of those quarantined in Vaud and Geneva were children. Alongside students, parents and siblings would also need to take a test to check for the variant.

The health authority did not say whether the new quarantine measures were related to the previously confirmed case, but said the two confirmed cases were “closely related within the family to a positive person returning from a trip to South Africa”.

The World Health Organisation declared that Omicron poses a “very high” global risk. As scientists analyze the data in the coming weeks, the epidemiological picture will become clearer.