At least 150 people who responded to a survey put out to guests who attended a catered event at the Russell Investments Center Building in downtown Seattle last Tuesday, report feeling ill afterwards.

An additional 50 cases were reported directly to Public Health — Seattle & King County.

Health department investigators have sent surveys to 600 people who attended the event. As of Monday morning, only 200 have responded.

All food service operations in the building at 1301 2nd Avenue have been shut down during the investigation and cleaning process. 

Health officials believe a private cafeteria inside the building may have been where the virus started.

Norovirus is highly contagious and quickly causes sickness.  It’s believed that people who may have been sickened by food then spread the virus.