COVID-19 in the homeless population: a scoping review and meta-analysis examining differences in prevalence, presentation, vaccine hesitancy and government response in the first year of the pandemic.

AIMS: People experiencing homelessness (PEH) have been identified as being increasingly susceptible to Coronavirus disease (COVID-19), with policies enacted to test, isolate, increase hygiene practices and prioritise vaccines among this population. Here, we conduct a scoping review of the current evidence-base pertaining to the prevalence and presentation of COVID-19 in PEH, COVID-vaccine hesitancy rates and government interventions enacted within the first year of the pandemic for PEH. MATERIALS AND METHODS: A systematic search was conducted on Pubmed, Cochrane, Embase and MedRxiv databases for studies reporting primary data on COVID-19 prevalence and clinical characteristics in PEH, vaccine uptake for PEH and policies enacted targeting PEH. Study qualities were assessed with The National Heart, Lung and Blood Institute's set of Study Quality. RESULTS: Eighty-three studies were included in our final analysis. The overall prevalence of symptomatic COVID-19 infection in PEH is estimated at 35%. The most common symptoms found were cough and shortness of breath, followed by fever. Concerns regarding vaccine hesitancy amongst PEH related to thoroughness of COVID-19 vaccine clinical trials, side effects and mistrust of the government. The main strategies implemented by governments were mass testing, adaption of healthcare service provision, provision of alternative housing, encouraging personal hygiene (hand sanitation and mask wearing), and inter-organisational communication. DISCUSSION: In our meta-analysis, 35% of PEH with a COVID-19 infection presented symptomatically; the low prevalence of symptomatic COVID-19 infection suggests widespread testing following outbreaks would be beneficial for this group of individuals. Temporary recuperation units and measures for housing stability in the pandemic, namely provision of alternative housing and stopping evictions, were found to be highly effective. High rates of vaccine hesitancy means that education and encouragement towards vaccination would be beneficial for this vulnerable population, where comorbidities are common. Finally increased focus in research should be placed on the mental health burden of COVID-19 and the pandemic on PEH moving forwards.

Implementation of rapid and frequent SARS-CoV2 antigen testing and response in congregate homeless shelters.

BACKGROUND: People experiencing homelessness who live in congregate shelters are at high risk of SARS-CoV2 transmission and severe COVID-19. Current screening and response protocols using rRT-PCR in homeless shelters are expensive, require specialized staff and have delays in returning results and implementing responses. METHODS: We piloted a program to offer frequent, rapid antigen-based tests (BinaxNOW) to residents and staff of congregate-living shelters in San Francisco, California, from January 15th to February 19th, 2021. We used the Reach-Effectiveness-Adoption-Implementation-Maintenance (RE-AIM) framework to evaluate the implementation. RESULTS: Reach: We offered testing at ten of twelve eligible shelters. Shelter residents and staff had variable participation across shelters; approximately half of eligible individuals tested at least once; few tested consistently during the study. Effectiveness: 2.2% of participants tested positive. We identified three outbreaks, but none exceeded 5 cases. All BinaxNOW-positive participants were isolated or left the shelters. Adoption: We offered testing to all eligible participants within weeks of the project's initiation. Implementation: Adaptations made to increase reach and improve consistency were promptly implemented. Maintenance: San Francisco Department of Public Health expanded and maintained testing with minimal support after the end of the pilot. CONCLUSION: Rapid and frequent antigen testing for SARS-CoV2 in homeless shelters is a viable alternative to rRT-PCR testing that can lead to immediate isolation of infectious individuals. Using the RE-AIM framework, we evaluated and adapted interventions to enable the expansion and maintenance of protocols.

Mortality Among People Experiencing Homelessness in San Francisco During the COVID-19 Pandemic.

Importance: There has been recent media attention on the risk of excess mortality among homeless individuals during the COVID-19 pandemic, yet data on these deaths are limited. Objectives: To quantify and describe deaths among people experiencing homelessness in San Francisco during the COVID-19 pandemic and to compare the characteristics of these deaths with those in prior years. Design, Setting, and Participants: A cross-sectional study tracking mortality among people experiencing homelessness from 2016 to 2021 in San Francisco, California. All deceased individuals who were homeless in San Francisco at the time of death and whose deaths were processed by the San Francisco Office of the Chief Medical Examiner were included. Data analysis was performed from August to October 2021. Exposure: Homelessness, based on homeless living status in an administrative database. Main Outcomes and Measures: Descriptive statistics were used to understand annual trends in demographic characteristics, cause and manner of death (based on autopsy), substances present in toxicology reports, geographic distribution of deaths, and use of health and social services prior to death. Total estimated numbers of people experiencing homelessness in San Francisco were assessed through semiannual point-in-time counts. The 2021 point-in-time count was postponed owing to the COVID-19 pandemic. Results: In San Francisco, there were 331 deaths among people experiencing homelessness in the first year of the COVID-19 pandemic (from March 17, 2020, to March 16, 2021). This number was more than double any number in previous years (eg, 128 deaths in 2016, 128 deaths in 2017, 135 deaths in 2018, and 147 deaths in 2019). Most individuals who died were male (268 of 331 [81%]). Acute drug toxicity was the most common cause of death in each year, followed by traumatic injury. COVID-19 was not listed as the primary cause of any deaths. The proportion of deaths involving fentanyl increased each year (present in 52% of toxicology reports in 2019 and 68% during the pandemic). Fewer decedents had contacts with health services in the year prior to their death during the pandemic than in prior years (13% used substance use disorder services compared with 20% in 2019). Conclusions and Relevance: In this cross-sectional study, the number of deaths among people experiencing homelessness in San Francisco increased markedly during the first year of the COVID-19 pandemic. These findings may guide future interventions to reduce mortality among individuals experiencing homelessness.

Hospitalizations for COVID-19 Among US People Experiencing Incarceration or Homelessness.

Importance: People experiencing incarceration (PEI) and people experiencing homelessness (PEH) have an increased risk of COVID-19 exposure from congregate living, but data on their hospitalization course compared with that of the general population are limited. Objective: To compare COVID-19 hospitalizations for PEI and PEH with hospitalizations among the general population. Design, Setting, and Participants: This cross-sectional analysis used data from the Premier Healthcare Database on 3415 PEI and 9434 PEH who were evaluated in the emergency department or were hospitalized in more than 800 US hospitals for COVID-19 from April 1, 2020, to June 30, 2021. Exposures: Incarceration or homelessness. Main Outcomes and Measures: Hospitalization proportions were calculated. and outcomes (intensive care unit admission, invasive mechanical ventilation [IMV], mortality, length of stay, and readmissions) among PEI and PEH were compared with outcomes for all patients with COVID-19 (not PEI or PEH). Multivariable regression was used to adjust for potential confounders. Results: In total, 3415 PEI (2952 men [86.4%]; mean [SD] age, 50.8 [15.7] years) and 9434 PEH (6776 men [71.8%]; mean [SD] age, 50.1 [14.5] years) were evaluated in the emergency department for COVID-19 and were hospitalized more often (2170 of 3415 [63.5%] PEI; 6088 of 9434 [64.5%] PEH) than the general population (624 470 of 1 257 250 [49.7%]) (P < .001). Both PEI and PEH hospitalized for COVID-19 were more likely to be younger, male, and non-Hispanic Black than the general population. Hospitalized PEI had a higher frequency of IMV (410 [18.9%]; adjusted risk ratio [aRR], 1.16; 95% CI, 1.04-1.30) and mortality (308 [14.2%]; aRR, 1.28; 95% CI, 1.11-1.47) than the general population (IMV, 88 897 [14.2%]; mortality, 84 725 [13.6%]). Hospitalized PEH had a lower frequency of IMV (606 [10.0%]; aRR, 0.64; 95% CI, 0.58-0.70) and mortality (330 [5.4%]; aRR, 0.53; 95% CI, 0.47-0.59) than the general population. Both PEI and PEH had longer mean (SD) lengths of stay (PEI, 9 [10] days; PEH, 11 [26] days) and a higher frequency of readmission (PEI, 128 [5.9%]; PEH, 519 [8.5%]) than the general population (mean [SD] length of stay, 8 [10] days; readmission, 28 493 [4.6%]). Conclusions and Relevance: In this cross-sectional study, a higher frequency of COVID-19 hospitalizations for PEI and PEH underscored the importance of adhering to recommended prevention measures. Expanding medical respite may reduce hospitalizations in these disproportionately affected populations.

Exploratory attitude survey of homeless persons regarding telecare services in shelters providing mid- and long-term accommodation: The importance of trust.

BACKGROUND: With the expansion of digital health, it is imperative to consider intervention techniques in order not to be the cause of even more social health inequalities in underserved populations struggling with chronic diseases. Telemedicine solutions for homeless persons might compensate for shortcomings in access to valuable health services in different settings. The main aim of our research was to examine the attitudes and openness of homeless persons regarding telecare on a Hungarian sample. METHODS: Quantitative survey among homeless people (n = 98) was completed in 4 shelters providing mid- and long-term accommodation in Budapest, Hungary. Attitudes regarding healthcare service accessibility and telecare were measured by a self-developed questionnaire of the research team. Telecare attitude comparison was made with data of a Hungarian weighted reference group of non-homeless persons recruited from 2 primary care units (n = 110). RESULTS: A significant fraction of homeless people with mid- or long-term residency in homeless shelters did not oppose the use of telecare via live online video consultation and there was no difference compared to the national reference group (averages of 3.09 vs. 3.15, respectively). Results of the homeless group indicate that those more satisfied with healthcare services, in general, manifest more openness to telecare. It is clearly demonstrated by the multivariate analysis that those participants in the homeless group who had problems getting health care in the last year definitely preferred in-person doctor-patient consultations. CONCLUSION: Digital health technologies offer a potentially important new pathway for the prevention and treatment of chronic conditions among homeless persons. Based on the attitudes towards telecare, initiating an on-site telecare program for mid- and long-term residents of homeless shelters might enable better care continuity. Our results draw attention to the key factors including building trust in the implementation of such programs among underserved and other vulnerable patient groups.

Estimation of Utility Values for Computing Quality-adjusted Life Years Associated With Homelessness.

BACKGROUND: There is a lack of data-driven evidence about the burden of homelessness, and lack of a holistic measure of effectiveness for evaluating interventions targeting homelessness. Quality-adjusted life years (QALYs) can help holistically capture the burden of homelessness, and facilitate the valuation and comparison of interventions designed to address homelessness. OBJECTIVE: This study estimated utility values required to compute the QALYs associated with homelessness, and also examined individual-level characteristics that affect these values. RESEARCH DESIGN: The study is cross-sectional and derived from a large national survey conducted during the coronavirus disease 2019 pandemic. SUBJECTS: A sample of 6607 middle- and low-income adults in the United States. MEASURES: A self-completion standard gamble survey was used to estimate utility values associated with homelessness. Linear regression was used to analyze the association between individual-level characteristics and these utility values. RESULTS: The study estimated the average utility value associated with homelessness as 43.4% among the study participants. This implies that 1 year of life as a homeless individual is perceived to be equivalent to less than half a year of life as a stably housed individual in good health. The study also found that individuals who have experienced homelessness and financial distress value life as a homeless person considerably less than those who have not had these experiences. CONCLUSIONS: The method developed in this study can be used to estimate QALYs in studies evaluating homelessness interventions, thereby establishing the societal value of these interventions and informing policy and budgetary decision-making. Future studies estimating the utility values associated with homelessness in the general population, as well as specific homeless groups, are required to provide more generalizable evidence.

Equal incidence of COVID-19 among homeless and non-homeless ED patients when controlling for confounders.

INTRODUCTION: The World Health Organization (WHO) declared severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) a pandemic in March 2020. Theoretically, homeless patients could have disproportionately worse outcomes from COVID-19, but little research has corroborated this claim. This study aimed to examine the demographics and incidence of COVID-19 in homeless vs non-homeless emergency department (ED) patients. METHODS: This is a retrospective study of all patients seen in the University of Louisville Hospital Emergency Department (ULH ED) from March 2019 to December 2020, excluding January and February 2020. Data was collected from the Kentucky Homeless Management Information System (HMIS) and ULH electronic health records. RESULTS: A total of 51,532 unique patients had 87,869 visits during the study period. There was a 18.1% decrease in homeless patient visits over the time period, which was similar to the decrease in non-homeless patient visits (19.2%). In the total population, 9471 individuals had known COVID-19 testing results, with a total of 610 positive (6.4% positivity rate). Of the 712 homeless ED patients, 39 tested positive (5.5% positivity rate). After adjusting for age, gender identity, race, and insurance, there was no statistically significant difference in test positivity between homeless and non-homeless patients, OR 1.23 (0.88, 1.73). Homeless patients were less likely to be admitted to either the intensive care unit (ICU) or hospital (OR = 0.55, 95% CI: OR 0.51, 0.60) as they were more likely to be discharged (OR = 1.65, 95% CI: 1.52, 1.79). CONCLUSION: Previous literature has indicated that higher disease burden, lack of access to social distancing, and poor hygiene would increase the risk of homeless individuals contracting COVID-19 and experiencing serious morbidity. However, this study found that homelessness was not an independent risk factor for COVID-19 infection.

Investigating the impacts of COVID-19 among LGBTQ2S youth experiencing homelessness.

BACKGROUND: LGBTQ2S youth are overrepresented among youth experiencing homelessness and experience significantly higher rates of mental health issues compared to heterosexual and cisgender youth. COVID-19 related challenges for LGBTQ2S youth experiencing homelessness remain unknown. To address this gap, this study aimed to understand the impacts of the COVID-19 pandemic on LGBTQ2S youth at risk of, and experiencing, homelessness in the Greater Toronto Area, Ontario, Canada and surrounding areas. METHODS: Utilizing a mixed-methods convergent parallel design, LGBTQ2S youth experiencing homelessness were recruited to participate in virtual surveys and in-depth one-on-one interviews. Surveys included standardized measures and were administered to measure mental health outcomes and collect information on demographic characteristics, and health service use. Survey data were analyzed with descriptive statistics and statistical tests for difference of proportions. Interviews were analyzed using an iterative thematic content approach. RESULTS: Sixty-one youth completed surveys and 20 youth participated in one-on-one interviews. Quantitative and qualitative data showed that youth have been significantly impacted by the COVID-19 pandemic in various ways, including experiencing poor mental health, such as suicidality, depression, anxiety, and increased substance use, and lack of access to health and social support services. CONCLUSION: Our study highlights the need for LGBTQ2S inclusive and affirming health care and support services for precariously housed adolescents to address the pre-existing social and health issues that have been exacerbated by the pandemic.

Seroprevalence of SARS-CoV-2 antibodies among homeless people living rough, in shelters and squats: A large population-based study in France.

BACKGROUND: Overcrowded housing, as well as inadequate sanitary conditions, contribute to making homeless people particularly vulnerable to the SARS-CoV-2 infection. We aimed to assess the seroprevalence of the SARS-CoV-2 infection among people experiencing homelessness on a large city-wide scale in Marseille, France, taking into account different types of accommodation. METHODS: A consortium of outreach teams in 48 different locations including streets, slums, squats, emergency or transitional shelters and drop-in centres participated in the inclusion process. All participants consented to have a validated rapid antibody assay for immunoglobulins M (IgM) and G (IgG) and to answer a questionnaire on medical health conditions, comorbidities, and previous COVID-19 symptoms. Information on their housing conditions since the COVID-19 crisis was also collected from the participants. RESULTS: From June 01 to August 05, 2020, 1,156 homeless participants were enrolled in the study and tested. The overall seroprevalence of SARS-CoV-2 IgG/IgM antibodies was 5.6% (95%CI 2.3-7.0), ranging from 2.2% in people living on the streets to 8.1% in people living in emergency shelters (P = 0.009). Around one third of the seropositive participants reported COVID-19 symptoms. Compared to the general population in Marseille (3.6%), the homeless population living in the same urban area experienced a significantly increased risk of SARS-CoV-2 infection (|z| = 3.65 > 1.96). CONCLUSION: These findings highlight the need for regular screening among the homeless to prevent clustering in overcrowded or inadequate accommodations. It is also necessary to provide essential resources to keep homeless people healthy, the vast majority of whom have cumulative risk factors for SARS-CoV-2 infection.

Assessment of SARS-CoV-2 Infection Prevalence in Homeless Shelters - Four U.S. Cities, March 27-April 15, 2020.

In the United States, approximately 1.4 million persons access emergency shelter or transitional housing each year (1). These settings can pose risks for communicable disease spread. In late March and early April 2020, public health teams responded to clusters (two or more cases in the preceding 2 weeks) of coronavirus disease 2019 (COVID-19) in residents and staff members from five homeless shelters in Boston, Massachusetts (one shelter); San Francisco, California (one); and Seattle, Washington (three). The investigations were performed in coordination with academic partners, health care providers, and homeless service providers. Investigations included reverse transcription-polymerase chain reaction testing at commercial and public health laboratories for SARS-CoV-2, the virus that causes COVID-19, over approximately 1-2 weeks for residents and staff members at the five shelters. During the same period, the team in Seattle, Washington, also tested residents and staff members at 12 shelters where a single case in each had been identified. In Atlanta, Georgia, a team proactively tested residents and staff members at two shelters with no known COVID-19 cases in the preceding 2 weeks. In each city, the objective was to test all shelter residents and staff members at each assessed facility, irrespective of symptoms. Persons who tested positive were transported to hospitals or predesignated community isolation areas.

Rapid Creation of a Multiagency Alternate Care Site for COVID-19- Positive Individuals Experiencing Homelessness.

Cook County Health partnered with the Chicago Departments of Public Health and Family & Support Services and several dozen community-based organizations to rapidly establish a temporary medical respite shelter during the spring 2020 COVID-19 peak for individuals experiencing homelessness in Chicago and Cook County, Illinois. This program provided low-barrier isolation housing to medically complex adults until their safe return to congregate settings. We describe strategies used by the health care agency, which is not a Health Resource and Services Administration Health Care for the Homeless grantee, to provide medical services and care coordination.

SARS-CoV-2 screening among people living in homeless shelters in Brussels, Belgium.

BACKGROUND: Subgroups of precarious populations such as homeless people are more exposed to infection and at higher risk of developing severe forms of COVID-19 compared to the general population. Many of the recommended prevention measures, such as social distancing and self-isolation, are not feasible for a population living in shelters characterised by physical proximity and a high population density. The objective of the study was to describe SARS-CoV-2 infection prevalence in homeless shelters in Brussels (Belgium), and to identify risk factors and infection control practices associated with SARS-CoV-2 positivity rates. METHODS: A total of 1994 adults were tested by quantitative PCR tests in 52 shelters in Brussels (Belgium) between April and June, 2020, in collaboration with Doctors of the World. SARS-CoV-2 prevalence is here described site by site, and we identify risk factors associated with SARS-CoV-2 positivity rates. We also investigate associations between seropositivity and reported symptoms. RESULTS: We found an overall prevalence of 4.6% for the period, and a cluster of high rates of SARS-CoV-2 positivity (20-30% in two shelters). Among homeless people, being under 40 years of age (OR (CI95%) 2.3 (1.2-4.4), p = 0.02), having access to urgent medical care (AMU) (OR(CI95%): 2.4 (1.4-4.4)], p = 0.02), and sharing a room with someone who tested positive (OR(CI95%): 5.3 (2.9-9.9), p<0.0001) were factors associated with SARS-CoV-2 positivity rates. 93% of those who tested positive were asymptomatic. CONCLUSION: This study shows high rates of SARS-COV-2 infection positive tests in some shelters, with a high proportion of asymptomatic cases. The survey reveals how important testing and isolation measures are, together with actions taken by medical and social workers during the outbreak.

Impact of the COVID-19 pandemic on the homeless: results from a retrospective closed cohort in France (March-May 2020).

OBJECTIVES: To evaluate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, hospitalization and fatality rates in residents of homeless shelters run by Samusocial of Paris. METHODS: We conducted a retrospective serological study between July and August 2020 on all residents and staff members of three homeless shelters run by Samusocial of Paris: two centres providing healthcare accommodation (HCA) and one a women's dormitory. We included all adults present in the shelters or who died of a proven SARS-CoV-2 infection during the first wave (March-May). SARS-CoV-2 antibodies were detected in serum samples using the SARS-CoV-2 IgG Architect (Abbott) test. Any participant with a positive PCR or serology was defined as a confirmed SARS-CoV-2 case. RESULTS: We included 100 residents and 83 staff members. The confirmed SARS-CoV-2 rate by PCR or serology was 72/100 (72.0%) for residents and 17/83 (20.5%) for staff members. Women accommodated in the dormitory had the highest infection rate (90.6%). The hospitalization rate in residents was 17/72 (23.6%) and the death rate 4/72 (5.6%). All hospitalizations and deaths occurred among HCA residents. Among the residents of HCA shelters, 34/68 (50%) presented at least two comorbidity factors associated with being at high risk for severe SARS-CoV-2 infection. CONCLUSION: The SARS-CoV-2 infection rate was high in residents of these homeless shelters (10.6% seroprevalence in the Île-de-France region during the first wave). Severe SARS-CoV-2 infection was highly associated with the prevalence of comorbidities. This population should be considered as a priority in vaccination campaigns and in access to individual housing units when at risk.

Morbidity and Mortality Among Adults Experiencing Homelessness Hospitalized With COVID-19.

People experiencing homelessness (PEH) are at higher risk for chronic health conditions, but clinical characteristics and outcomes for PEH hospitalized with coronavirus disease 2019 (COVID-19) are not known. We analyzed population-based surveillance data of COVID-19-associated hospitalizations during 1 March to 31 May 2020. Two percent of the people hospitalized with COVID-19 for whom a housing status was recorded were homeless. Of 199 cases in the analytic sample, most were of racial/ethnic minority groups and had underlying health conditions. Clinical outcomes such as ICU admission, respiratory support including mechanical ventilation, and deaths were documented. Hispanic and non-Hispanic black persons accounted for most mechanical ventilation and deaths. Severe illness was common among persons experiencing homelessness who were hospitalized with COVID-19.

Projecting COVID-19 isolation bed requirements for people experiencing homelessness.

As COVID-19 spreads across the United States, people experiencing homelessness (PEH) are among the most vulnerable to the virus. To mitigate transmission, municipal governments are procuring isolation facilities for PEH to utilize following possible exposure to the virus. Here we describe the framework for anticipating isolation bed demand in PEH communities that we developed to support public health planning in Austin, Texas during March 2020. Using a mathematical model of COVID-19 transmission, we projected that, under no social distancing orders, a maximum of 299 (95% Confidence Interval: 223, 321) PEH may require isolation rooms in the same week. Based on these analyses, Austin Public Health finalized a lease agreement for 205 isolation rooms on March 27th 2020. As of October 7th 2020, a maximum of 130 rooms have been used on a single day, and a total of 602 PEH have used the facility. As a general rule of thumb, we expect the peak proportion of the PEH population that will require isolation to be roughly triple the projected peak daily incidence in the city. This framework can guide the provisioning of COVID-19 isolation and post-acute care facilities for high risk communities throughout the United States.

Comparison of infection control strategies to reduce COVID-19 outbreaks in homeless shelters in the United States: a simulation study.

BACKGROUND: COVID-19 outbreaks have occurred in homeless shelters across the US, highlighting an urgent need to identify the most effective infection control strategy to prevent future outbreaks. METHODS: We developed a microsimulation model of SARS-CoV-2 transmission in a homeless shelter and calibrated it to data from cross-sectional polymerase chain reaction (PCR) surveys conducted during COVID-19 outbreaks in five homeless shelters in three US cities from March 28 to April 10, 2020. We estimated the probability of averting a COVID-19 outbreak when an exposed individual is introduced into a representative homeless shelter of 250 residents and 50 staff over 30 days under different infection control strategies, including daily symptom-based screening, twice-weekly PCR testing, and universal mask wearing. RESULTS: The proportion of PCR-positive residents and staff at the shelters with observed outbreaks ranged from 2.6 to 51.6%, which translated to the basic reproduction number (R0) estimates of 2.9-6.2. With moderate community incidence (~ 30 confirmed cases/1,000,000 people/day), the estimated probabilities of averting an outbreak in a low-risk (R0 = 1.5), moderate-risk (R0 = 2.9), and high-risk (R0 = 6.2) shelter were respectively 0.35, 0.13, and 0.04 for daily symptom-based screening; 0.53, 0.20, and 0.09 for twice-weekly PCR testing; 0.62, 0.27, and 0.08 for universal masking; and 0.74, 0.42, and 0.19 for these strategies in combination. The probability of averting an outbreak diminished with higher transmissibility (R0) within the simulated shelter and increasing incidence in the local community. CONCLUSIONS: In high-risk homeless shelter environments and locations with high community incidence of COVID-19, even intensive infection control strategies (incorporating daily symptom screening, frequent PCR testing, and universal mask wearing) are unlikely to prevent outbreaks, suggesting a need for non-congregate housing arrangements for people experiencing homelessness. In lower-risk environments, combined interventions should be employed to reduce outbreak risk.