By Ben Warwick

SUMMIT COUNTY, Colo. (CBS4) – Health Department officials in Summit County say a mumps outbreak at Keystone has grown. As of Wednesday, 23 people now have confirmed cases.

Officials say they are working closely with the Colorado Department of Public Health and Environment in an ongoing local investigation. Of the confirmed cases, 21 are employees at the resort.

RELATED: Keystone Mumps Outbreak: 6th Employee Diagnosed With Viral Disease

Health officials partnered with Vail Resorts to hold a vaccine clinic earlier this week. A health department spokesperson said the number of cases could increase in the coming days, but the risk to the public remains low.

Ben Warwick