Mumps Cases Reported in Migrant Detention Centers a Likely Harbinger

Troy Brown, RN

August 29, 2019

Mumps outbreaks continue in multiple migrant detention facilities in the United States, putting detainees, facility staff, and surrounding communities at risk for infection, the Centers for Disease Control and Prevention (CDC) says.

There have been 898 confirmed and probable cases of mumps among adult migrants detained in 57 US Immigration and Customs Enforcement (ICE) detention facilities in 19 states in less than a year. An additional 33 cases were reported among staff members.

The cases occurred between September 1, 2018, and August 22, 2019, Jessica Leung, MPH, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, CDC, and colleagues report in an article published online today in Morbidity and Mortality Weekly Report.

The 57 affected detention facilities represent 18% of the 315 facilities that house ICE detainees in the United States.

Canary in a Coal Mine?

"I see this as something like a canary in the coal mine phenomenon," Jeffrey S. Duchin, MD, health officer and chief, Communicable Disease Epidemiology and Immunization Section, Public Health–Seattle and King County, and professor of medicine, Division of Infectious Diseases, University of Washington, told Medscape Medical News.

"If mumps can spread like this, so will influenza, so will other respiratory diseases, potentially pertussis, perhaps meningococcal disease, pneumococcal pneumonia. If people are held long enough, even tuberculosis can spread in an environment like that," Duchin said.

The affected facilities first reported five confirmed cases of mumps on October 12, 2018. The cases, which occurred among migrants who had been transferred between two detention facilities in Texas, were reported to the Texas Department of State Health Services (TDSHS).

By December 11, another 67 cases at eight detention facilities in Texas and six facilities in five other states had been reported to ICE Health Service Corps (IHSC) or local health departments. The next day, the TDSHS contacted the CDC to discuss ways to control mumps in detention facilities and to make communication with the IHSC easier.

The CDC and the IHSC began a coordinated national outbreak response after another six state health departments reported new cases in detention facilities during January 4 to 17.

"The classic way in which public health authorities control outbreaks of infectious disease involve tracing of people who are exposed and monitoring of their symptoms and isolating them, and those steps are really not possible in this environment," Duchin explained.

Private companies operated 34 of the facilities; 19 facilities were in county jails that housed detained migrants. ICE operated four facilities.

Almost half of cases (44%; 394 cases) were reported by facilities in Texas. The median age of patients was 25 years (range, 17 – 67); 846 patients (94%) were male.

Most patients (758; 84%) were exposed to mumps while in ICE custody or the custody of another US agency, as determined on the basis of detainee custody status during the incubation period, which is 12 to 25 days before symptoms begin. Five percent (43 patients) were exposed before they were apprehended. The custody status at the time of exposure was unknown for 11% (97 patients) .

Among patients for whom data regarding complications were available, 15% (79 of 527 male patients) developed orchitis, and at least 13 patients required hospitalization.

Quantitative reverse transcription–polymerase chain reaction testing or viral culture testing confirmed 64% of mumps cases (576 cases); testing was conducted at the CDC, state public health laboratories, Association of Public Health Laboratories–CDC Vaccine Preventable Disease Reference Centers, or commercial laboratories.

Genotype G, "the most common mumps genotype detected in the United States since 2006," was responsible for illness in all 70 patients for whom sequencing of isolates was conducted, the authors write.

Prevention Is Key

Duchin said it is much more effective to prevent the transmission of an infectious disease such as mumps than it is to control an outbreak after it occurs.

"As long as the population is not adequately immunized and new people continue to be brought in that are susceptible, the spread of infectious diseases in these types of facilities will likely be an ongoing challenge," Duchin explained. Environmental measures to decrease the risk for transmission are also important, he added.

The IHSC provided more than 25,000 doses of measles-mumps-rubella (MMR) vaccine to 56 affected facilities.

Approximately 150 outbreaks and 16,000 cases of mumps have been reported in the United States since 2015. These have most often occurred in close-contact settings, including universities, schools, and athletic events. This is the first time mumps outbreaks in detention facilities are being reported.

As of August 22, 2019, mumps outbreaks continued in 15 detention facilities in seven states. Detainees who are transferred or who were exposed before they were taken into custody continue to introduce mumps into detention facilities.


Detention facilities vary with respect to MMR vaccination efforts. Facilities should follow recommendations from their local or state health departments for preventing and handling mumps, according to the CDC report. Facilities should report mumps cases and follow their health department's guidance regarding disease control.

Facilities should offer MMR vaccine to detainees and staff members who are at increased risk for mumps, according to current recommendations for vaccination during outbreaks.

"MMR vaccine has not been shown to be effective at preventing disease in persons already infected with mumps; facilities should be aware that cases might occur among detainees exposed before vaccination," the authors write.

The authors urge health departments, the CDC, the IHSC, and facility health administrators to develop appropriate measures to control the spread of mumps on the basis of local epidemiology and each facility's specific needs.

"It's really important for the people who manage these facilities to recognize the significant risk of the spread of infectious diseases both to those people who are confined and to the people who work there and potentially to the surrounding communities," Duchin said.

The authors acknowledge that it is challenging to identify and vaccinate close contacts of detainees who have been exposed or who have symptoms and say, "IHSC can look up transfer history and facilitate vaccine procurement for detainees in ICE custody upon request from facility health services administrators."

The CDC is working with the appropriate health departments, the IHSC, and other federal organizations to mobilize resources and is giving technical assistance for implementing measures to control and prevent the spread of mumps.

"Effective public health interventions require understanding of facility and custody operations, which often involve frequent transfers of detainees (between facilities and states) and multiple entities with authority for operations and detainee custody," the authors conclude.

The authors and Duchin have disclosed no relevant financial relationships.

Morb Mortal Wkly Rep. Published online August 29, 2019. Full text

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