(Bloomberg) -- The omicron variant is spreading so quickly that it could account for more than half of Covid-19 cases in Europe in a few months, a key European health agency said on Thursday.

The European Centre for Disease Prevention and Control said its estimate was based on preliminary data from South Africa and the variant’s characteristics still need further study before drawing any firm conclusions. 

Globally, there are at least 352 confirmed cases in 27 countries, including 70 cases in 13 European countries, according to public reports the ECDC compiled for its latest threat assessment.

The agency said that travel restrictions applied to southern Africa should be reassessed regularly and may become ineffective over the next few weeks as the variant continues to spread.

“Given the increasing number of cases and clusters in the EU/EEA without a travel history or contact with travel-related cases, it is likely that within the coming weeks the effectiveness of travel-related measures will significantly decrease, and countries should prepare for a rapid and measured de-escalation of such measures,” the agency said.

The ECDC also said the variants mutations may reduce the effectiveness of current antibodies induced by vaccination or infection, but more data is needed.

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