Google has pushed back its January 10 timeline to begin a hybrid work model for employees in the United States, Europe, the Middle East and Africa, according to reports Thursday, amid uncertainties about how contagious the coronavirus’ new omicron variant is and as more countries report cases of the variant.

Chris Rackow — Google’s vice president of global security — told U.S. employees in an email Thursday they will not be required to start a hybrid work model on the planned date, and the company will decide next year when to end remote work, CNBC reported.

Rackow didn’t mention the omicron variant as a reason for the delay, according to CNBC.

Matt Brittin, the president of Google’s Europe, the Middle East and Africa (EMEA) region, said in a memo obtained by Insider that offices in those regions will decide when to bring employees back to the office depending on local conditions.

Brittin reportedly said the decision stemmed from uncertainty sparked by omicron, as scientists are still trying to understand how contagious or transmittable it is and evaluate existing vaccines’ effectiveness against it.

A Google spokesperson told Forbes it will determine when to begin hybrid work based on local conditions, and it has opened 90% of offices in the United States, but did not confirm reports about changes in the EMEA region and the U.S.