Data on International Classification of Diseases diagnosis for influenza, varicella, and mumps were obtained from January 1, 2017, to March 22, 2020, and plotted by date of diagnosis. The total numbers of cases of each infection across 17 US Immigration and Customs Enforcement (ICE) detention centers that reported cases are shown for influenza (A), varicella (B), and mumps (C).
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Lo NC, Nyathi S, Chapman LAC, et al. Influenza, Varicella, and Mumps Outbreaks in US Migrant Detention Centers. JAMA. 2021;325(2):180–182. doi:10.1001/jama.2020.20539
In 2019, the US Immigration and Customs Enforcement (ICE) agency detained 510 854 migrants.1 Detention centers have poor living standards and environmental crowding that may facilitate infectious disease transmission.2,3 We documented outbreaks of influenza, varicella, and mumps among involuntarily detained migrants.
We obtained data on clinical influenza, varicella, and mumps cases among migrants in a subset of ICE detention centers from January 1, 2017, to March 22, 2020, through a formal request to ICE and the Department of Homeland Security. We received deidentified individual-level case data for ICE detention centers where the ICE Health Service Corp is the facility medical authority and uses the ICE electronic health record system (22 of 315 centers).2 Data were obtained by ICE officials through chart review using International Classification of Diseases (ICD) diagnosis codes alone. We analyzed summary statistics for infections by date, age, and facility. We defined an outbreak as 3 or more cases linked in time and place over a 1-month period, with outbreak duration defined by occurrence of 3 or more cases per contiguous month. This project was considered exempt non–human subjects research by the institutional review board at the University of California, San Francisco. Analytic code (R version 4.0.2) and data are available from the authors.
Among 22 ICE detention centers, 1280 influenza, 1052 varicella, and 301 mumps cases were identified among migrants in 17 centers (Figure). Fifteen centers had at least 1 outbreak. We identified 41 influenza outbreaks in 13 detention centers with a mean duration of 2.0 (range, 1-14) months and a mean size of 24 (range, 3-402) cases; 26 varicella outbreaks in 9 detention centers with a mean duration of 3.4 (range, 1-33) months and a mean size of 46 (range, 3-494) cases; and 12 mumps outbreaks in 8 detention centers with a mean duration of 2.4 (range, 1-9) months and a mean size of 18 (range, 3-62) cases (Table). Cases of influenza and varicella occurred throughout the study period, while most mumps cases occurred between September 2018 and January 2020. Mean ages among influenza, varicella, and mumps cases were 21.6 (range, 0-82) years, 18.2 (range, 0-77) years, and 28.7 (range, 18-77) years, respectively. The age distributions of observed cases for influenza and varicella were bimodal, with peaks at 4 and 24 years for influenza and at 5 years and 21 years for varicella. A total of 62.9% of infections occurred among adults. Of all infections, 44.7% occurred in the South Texas Family Residential Center and 16.5% in the Port Isabel Service Processing Center.
This study identified recurrent outbreaks of 3 vaccine-preventable infectious diseases among migrants involuntarily held in ICE detention centers. A large number of cases occurred in 2 centers. Outbreaks in different centers may be related, given the common practice of moving detainees between centers.2 Most varicella cases occurred among adults, who are often susceptible and predisposed to greater clinical severity.4 Waning immunity against mumps among vaccinated adults is well documented, suggesting that many adult migrants remain susceptible to mumps; revaccination confers at least near-term protection.5 Sustained influenza transmission was identified, with cases occurring year-round.
This analysis has limitations. Released data covered only 22 detention centers with 17 reporting cases, and chart review of clinical data likely missed cases; an independent audit of accuracy and completeness was not possible because ICE officials performed the chart review and data extraction. Case counts were defined by ICD codes, suggesting imperfect specificity. Census data on age distributions of all migrants detained in each center and data on movement of migrants between centers were not provided. In centers with multiple outbreaks, outbreaks may be related rather than distinct and influenced by underreporting of cases and by the study definition of an outbreak.
ICE detention centers are high-risk environments for infectious disease outbreaks due to crowding, poor health conditions, limited access to preventive measures including immunizations, and baseline underimmunization in this migrant population.2,3,6 Currently, routine vaccination on entry to ICE detention centers is conducted only in limited instances for children. A policy change to offer expanded routine vaccination on entry for children and adults along with improvements in health care access and infection prevention practices in detention centers is warranted.
Corresponding Author: Nathan C. Lo, MD, PhD, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110 (email@example.com).
Accepted for Publication: September 30, 2020.
Published Online: October 29, 2020. doi:10.1001/jama.2020.20539
Author Contributions: Dr Lo had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: Lo.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Lo.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Lo, Nyathi.
Administrative, technical, or material support: All authors.
Conflict of Interest Disclosures: Dr Lo reported receipt of grants and personal fees from the World Health Organization and the California Department of Public Health. Dr Kushel reported receipt of grants from the National Institute on Aging. Dr Lewnard reported receipt of grants and personal fees from Merck Sharp & Dohme and Pfizer. None of the reported funding is related to the current work. No other disclosures were reported.
Funding/Support: Dr Lo is supported by the Department of Medicine at the University of California, San Francisco.
Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Additional Contributions: We acknowledge the officials who collected these data.
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