OMD UK has been forced to shutter its central London offices for at least the next 48 hours over coronavirus fears.
An all-staff email seen by The Drum revealed how employees from its Fitzrovia office have been asked to work from home until further notice.
The closure marks the first major disruption the virus has caused for the UK ad industry. Until the end of the week at least, OMD's clients — which include McDonald's, Apple, Nissan and TikTok — will face some upheaval with staff working remotely.
In a statement, Omnicom said concerns were raised on Wednesday after an employee who had recently returned from Australia from a flight connection through Singapore began showing "flu-like" symptoms.
"As a precautionary measure, and until definitive results of the employee’s coronavirus test are confirmed, we are asking OMG employees at our Fitzrovia offices to immediately work from home," it wrote.
"OMG UK employees have been informed that, whilst the risk of the test being positive is minimal, every precaution is being taken to protect their health and wellbeing,"
The all-staff email (which included advice on what to do if people experienced any symptoms of the virus) read:
"As a precautionary measure, employees at OMD UK will be working from home across the next 48 hours (until further notice).
"If you were working or visiting OMD UK yesterday, we would ask that you work from home across the next 48 hours. If you feel unwell, please follow the advice below.
"While the risk of anyone being tested positive is minimal, we want to take every precaution to protect your health and wellbeing. Please inform your line manager if you need to work from home.
"We will continue to keep you informed of any changes to their advice"
OMD UK's closure comes as several European countries have announced their first coronavirus cases, all apparently linked to a growing outbreak in Italy.
Austria, Croatia, Greece and Switzerland said the cases involved people who had been to Italy, as did Algeria in Africa. In the UK, 13 cases have already been confirmed.
The virus has already prompted ad agency networks including WPP and InterPublic Group to restrict staff travel to China, where the outbreak began.