By Kathy Walsh

DENVER (CBS4)– Public health officials are investigating an outbreak of six mumps cases in Denver County. The outbreak is among a group of residents and health care personnel.

Officials believe the source of the infection is thought to be a person who recently moved to Colorado from Iowa with additional infections resulting from exposures in a health care setting. Iowa has been experiencing an ongoing outbreak of mumps since July 2015.

(credit: CBS)

(credit: CBS)

While infectious, the person socialized with a group of three friends who all subsequently developed unilateral parotid swelling and tenderness in late January. Those people were evaluated and treated for mumps at the Denver Adult Urgent Care Clinic on Feb. 2.

“All had some jaw swelling in this region which is pretty common for mumps. They also had low grade temperatures and just felt ill,” infectious disease Dr. Heather Young told CBS4 Health Specialist Kathy Walsh.

CBS4 Health Specialist Kathy Walsh interviews Dr. Heather Young (credit: CBS)

CBS4 Health Specialist Kathy Walsh interviews Dr. Heather Young (credit: CBS)

Young is a physician at Denver Health Medical Center and serves as the hospital’s epidemiologist.

Twenty days later, two health care personnel who treated those patients at the urgent care clinic developed symptoms consistent with mumps.

“Not having a high awareness that mumps is in the community leads to other spread,” said Young.

Young said all six of the adult patients had been vaccinated against the disease. She said the mumps vaccine is about 88 percent effective and immunity can wane after about 15 to 20 years.
“Right now, we’re not recommending another vaccine. But we’ll wait for further guidance from the CDPHE (Colorado Department of Public Health and Environment),” said Young.

Mumps cases are usually mild, but some can have serious complications.

“Some of those are inflammation of the brain or encephalitis, inflammation of the testes which can lead to fertility problems in men or inflammation of the ovaries or breasts in women,” explained Young.

Denver Health is contacting those who visited Denver Health Adult Urgent Care Clinic on Jan. 28, 30, 31, Feb. 2.

Additional Information from the Colorado Department of Health and Environment:

Mumps is a viral infection that can cause painful swelling of one or more of the salivary glands, typically the parotid glands. Other symptoms may include low-grade fever, malaise, and headache, but approximately one third of infected persons do not have clinically apparent illness so cases often go undetected. Severe complications from mumps are rare, but can include inflammation of the brain and/or tissue covering the brain and spinal cord, inflammation of the ovaries and/or breast, sterility, orchitis, spontaneous abortion, or deafness. Despite high vaccination rates and an effective vaccine, cases are likely to occur among vaccinated individuals because the vaccine is not 100 percent effective (estimated effectiveness for two doses is 88 percent) and vaccine-induced immunity can wane.


Mumps is transmitted by direct contact with respiratory droplets or saliva from an infected person. Mumps may be spread by freshly contaminated fomites. The average incubation period is 16-18 days, with a range of 12-25 days. The period of maximum communicability is from 1 to 2 days before onset of salivary gland swelling to 5 days after onset of salivary gland swelling. For disease investigation purposes, consider mumps cases infectious 2 days prior to salivary gland swelling through 6 days of swelling (5 days after swelling onset with the day of onset counted as day 0).

Kathy Walsh is CBS4’s Weekend Anchor and Health Specialist. She has been with CBS4 for more than 30 years. She is always open to story ideas. Follow Kathy on Twitter @WalshCBS4.