Since September 2018, 898 mumps cases were reported among detainees at U.S. Immigration and Customs Enforcement (ICE) facilities across 18 states. Tri-County Health Department (CO) managed a mumps outbreak at a contract ICE Processing Center in Aurora, Colorado. In under one week, the facility completed universal MMR vaccination for detainees; mumps transmission ceased twelve days later.

In February 2019, the Colorado Department of Public Health and Environment (CDPHE) learned of a mumps outbreak at a privately-run U.S. ICE Processing Center in Aurora, Colorado. The Aurora facility is Colorado’s largest ICE contract facility and houses approximately 1,500 detainees. Tri-County Health Department (TCHD) partnered with CDPHE to manage the outbreak, which posed unique challenges within this institutionalized setting: close physical contact in confined spaces; frequent influx of new detainees; transfer of detainees between ICE facilities; and likely low or unknown mumps vaccination status amongst detainees. Some detainees were exposed to mumps prior to arriving at the facility. However, throughout the course of the outbreak, detainees could develop illness within the ICE facility, while in transit to a different ICE facility, or once released into the surrounding community. Prior to public health intervention, the facility was not familiar with the measures necessary to track, test, report, or prevent new mumps cases. Initially, the facility’s only disease control method was to isolate symptomatic detainees and cohort detainee housing units that had been exposed to mumps cases. Within the housing units, there were multiple generations of new mumps cases, showing evidence of ongoing transmission among detainees within the facility.

TCHD led the outbreak investigation and response to stop immediate transmission of mumps and mitigate the risk of future outbreaks. Upon initial notification of mumps cases at the facility, CDPHE recommended that all detainees and facility staff voluntarily receive a single dose of measles, mumps, rubella (MMR) vaccine as a primary disease control measure to prevent mumps transmission within the facility. During February 19-25, 2019, TCHD engaged in daily communication with facility leadership, health services staff, and corporate liaisons to discuss the logistics of a mass vaccination program and provide guidance. Considerations included: accessing bulk supply of MMR vaccine; staff capacity/training to promptly screen and administer doses to more than 1300 detainees; vaccine storage and handling; and proper documentation. Timely implementation of a mass vaccination program required collaboration between public health, local and corporate facility leadership, and ICE Health Services Corps.

In response to the continuous influx of detainees and the ongoing risk of introducing new mumps cases, efforts were needed to maintain high MMR vaccination rates among detainees. TCHD worked with the facility to develop processes to sustain supplies of MMR vaccine and offer a dose to new detainees within 72 hours of arrival.

On February 22, 2019, the facility received 1170 MMR doses for detainee vaccination. Facility-wide mass vaccination efforts began on February 25, 2019. Within five days, the facility health services staff and TCHD nurses offered MMR vaccine to 1348 detainees, of which 1140 (85%) detainees received a dose. Seventeen (57%) of 30 detainee housing units had MMR vaccine uptake ranging from 90-100% immediately following these efforts. TCHD nurses held five on-site vaccine clinics to provide MMR vaccine to staff using federally funded vaccine supplied to public health for outbreak response. Of the 270 facility staff, 217 (80%) either showed documentation of previous MMR vaccination or received a dose from TCHD. The final outbreak case of mumps experienced illness onset on March 9, 2019, just 12 days after implementing the mass vaccination program. Subsequently, prompt vaccination of incoming detainees sustained facility wide vaccination rates between 65-85% through the end of the outbreak. Universal MMR vaccination proved highly effective in interrupting mumps transmission and ending the outbreak. Sustained vaccination efforts also lessened the risk of additional outbreaks if new mumps cases were introduced into the facility. Furthermore, public health did not detect community spread of mumps outside the facility.

Universal MMR vaccination of detainees and staff proved to be the most effective method to stop a mumps outbreak within a contract ICE Processing Center in Aurora, Colorado. As mumps cases in ICE detention centers increase nationally, state and local public health agencies may face similar scenarios as Colorado. Addressing a mumps outbreak in this novel setting required strong partnership between TCHD, CDPHE, and facility leadership, health services staff, and corporate liaisons. Clear and open communication, transparency, and advocacy were key to establishing an effective collaboration with the facility. Sharing standard public health outbreak recommendations for case ascertainment, isolation, and quarantine was an important component of disease control. But alone, those steps were not sufficient to successfully curb the outbreak in a detention center housing numerous detainees who were likely susceptible to mumps. Implementation of a mass MMR vaccination program and sustaining vaccination along with other disease control efforts required an understanding of the facility’s capacity as well as limitations. TCHD and CDPHE needed to adapt routine public health measures to meet the needs of the facility. We encourage public health agencies in jurisdictions with detention facility-associated mumps outbreaks to strengthen relationships with facility leadership and explore universal vaccination.