PORTLAND, Ore. (KOIN) — Over a dozen people became sick after attending a staff party at the Oregonian late last month, health officials confirmed.

At least 14 people reported coming down with diarrhea, stomach pain and vomiting within 24 hours of the cake-and-coffee celebration on May 31.

Two people tested positive for norovirus, Multnomah County Health officials said.

The department is now investigating the outbreak of gastrointestinal illness among the Oregonian’s staff, although health officials believe it was an isolated event.

There is reportedly no risk to the public.