Clinical Outcomes, Costs, and Cost-effectiveness of Strategies for Adults Experiencing Sheltered Homelessness During the COVID-19 Pandemic

Mitigating the COVID-19 Pandemic through Data-Driven Resource Sharing

COVID-19 outbreaks in local communities can result in a drastic surge in demand for scarce resources such as mechanical ventilators. To deal with such demand surges, many hospitals (1) purchased large quantities of mechanical ventilators, and (2) canceled/postponed elective procedures to preserve care capacity for COVID-19 patients. These measures resulted in a substantial financial burden to the hospitals and poor outcomes for non-COVID-19 patients. Given that COVID-19 transmits at different rates across various regions, there is an opportunity to share portable healthcare resources to mitigate capacity shortages triggered by local outbreaks with fewer total resources. This paper develops a novel data-driven adaptive robust simulation-based optimization (DARSO) methodology for optimal allocation and relocation of mechanical ventilators over different states and regions. Our main methodological contributions lie in a new policy-guided approach and an efficient algorithmic framework that mitigates critical limitations of current robust and stochastic models and make resource-sharing decisions implementable in real-time. In collaboration with epidemiologists and infectious disease doctors, we give proof of concept for the DARSO methodology through a case study of sharing ventilators among regions in Ohio and Michigan. The results suggest that our optimal policy could satisfy ventilator demand during the first pandemic's peak in Ohio and Michigan with 14% (limited sharing) to 63% (full sharing) fewer ventilators compared to a no sharing strategy (status quo), thereby allowing hospitals to preserve more elective procedures. Furthermore, we demonstrate that sharing unused ventilators (rather than purchasing new machines) can result in 5% (limited sharing) to 44% (full sharing) lower expenditure, compared to no sharing, considering the transshipment and new ventilator costs.

Interventions to mitigate the risks of COVID-19 for people experiencing homelessness and their effectiveness: a systematic review

Objectives

People experiencing homelessness also experience poorer clinical outcomes of COVID-19. Various interventions were implemented for people experiencing homelessness in 2020-2022 in different countries in response to varied national guidance to limit the impact of COVID-19. It is important to understand what was done and the effectiveness of such interventions. This systematic review aims to describe interventions to mitigate the risks of COVID-19 in people experiencing homelessness and their effectiveness.

Methods

A protocol was developed and registered in PROSPERO. Nine databases were searched for studies on interventions to mitigate the impact of COVID-19 on people experiencing homelessness. Included studies were summarised with narrative synthesis.

Results

From 8,233 references retrieved from the database searches and handsearching, 15 were included. There was a variety of interventions, including early identification of potential COVID-19 infections, provision of isolation space, healthcare support, and urgent provision of housing regardless of COVID-19 infection.

Conclusion

The strategies identified were generally found to be effective, feasible, and transferable. This review must be interpreted with caution due to the low volume of eligible studies and the low quality of the evidence available.

The optimisation of public health emergency governance: a simulation study based on COVID-19 pandemic control policy

BACKGROUND

The outbreak of the COVID-19 pandemic sparked numerous studies on policy options for managing public health emergencies, especially regarding how to choose the intensity of prevention and control to maintain a balance between economic development and disease prevention.

METHODS

We constructed a cost-benefit model of COVID-19 pandemic prevention and control policies based on an epidemic transmission model. On this basis, numerical simulations were performed for different economies to analyse the dynamic evolution of prevention and control policies. These economies include areas with high control costs, as seen in high-income economies, and areas with relatively low control costs, exhibited in upper-middle-income economies.

RESULTS

The simulation results indicate that, at the outset of the COVID-19 pandemic, both high-and low-cost economies tended to enforce intensive interventions. However, as the virus evolved, particularly in circumstances with relatively rates of reproduction, short incubation periods, short spans of infection and low mortality rates, high-cost economies became inclined to ease restrictions, while low-cost economies took the opposite approach. However, the consideration of additional costs incurred by the non-infected population means that a low-cost economy is likely to lift restrictions as well.

CONCLUSIONS

This study concludes that variations in prevention and control policies among nations with varying income levels stem from variances in virus transmission characteristics, economic development, and control costs. This study can help researchers and policymakers better understand the differences in policy choice among various economies as well as the changing trends of dynamic policy choices, thus providing a certain reference value for the policy direction of global public health emergencies.

A systematic review of the international evidence on the effectiveness of COVID-19 mitigation measures in communal rough sleeping accommodation

BACKGROUND

Accommodations with shared washing facilities increase the risks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection for people experiencing rough sleeping and evidence on what interventions are effective in reducing these risks needs to be understood.

METHODS

Systematic review, search date 6 December 2022 with methods published a priori. Electronic searches were conducted in MEDLINE, PubMed, Cochrane Library, CINAHL and the World Health Organization (WHO) COVID-19 Database and supplemented with grey literature searches, hand searches of reference lists and publication lists of known experts. Observational, interventional and modelling studies were included; screening, data extraction and risk of bias assessment were done in duplicate and narrative analyses were conducted.

RESULTS

Fourteen studies from five countries (USA, England, France, Singapore and Canada) were included. Ten studies were surveillance reports, one was an uncontrolled pilot intervention, and three were modelling studies. Only two studies were longitudinal. All studies described the effectiveness of different individual or packages of mitigation measures.

CONCLUSIONS

Despite a weak evidence base, the research suggests that combined mitigation measures can help to reduce SARS-CoV-2 transmission but are unlikely to prevent outbreaks entirely. Evidence suggests that community prevalence may modify the effectiveness of mitigation measures. More longitudinal research is needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021292803.

Cost of the COVID-19 pandemic versus the cost-effectiveness of mitigation strategies in EU/UK/OECD: a systematic review

OBJECTIVES

The economic burden of COVID-19 pandemic is substantial, with both direct and indirect costs playing a significant role.

DESIGN

A systematic literature review was conducted to estimate the cost of the COVID-19 pandemic and the cost-effectiveness of pharmaceutical or non-pharmaceutical interventions. All cost data were adjusted to the 2021 Euro, and interventions compared with null.

DATA SOURCES

Ovid MEDLINE and EMBASE were searched from January 2020 through 22 April 2021.

ELIGIBILITY CRITERIA

Studies regarding COVID-19 outbreak or public health preparedness measures or interventions with outcome measures related to the direct and indirect costs for disease and preparedness and/or response in countries of the European Union (EU), the European Economic Area (EEA), the UK and the Organisation for Economic Co-operation and Development (OECD) of all relevant epidemiological designs which estimate cost within the selected time frame were considered eligible.

DATA EXTRACTION AND SYNTHESIS

Studies were searched, screened and coded independently by two reviewers with high measure of inter-rater agreement. Data were extracted to a predefined data extraction sheet. The risk of bias was assessed using the Consensus on Health Economic Criteria checklist.

RESULTS

We included data from 41 economic studies. Ten studies evaluated the cost of the COVID-19 pandemic, while 31 assessed the cost-benefit of public health surveillance, preparedness and response measures. Overall, the economic burden of the COVID-19 pandemic was found to be substantial. Community screening, bed provision policies, investing in personal-protective-equipment and vaccination strategies were cost-effective. Physical distancing measures were associated with health benefits; however, their cost-effectiveness was dependent on the duration, compliance and the phase of the epidemic in which it was implemented.

CONCLUSIONS

COVID-19 pandemic is associated with substantial short-term and long-term economic costs to healthcare systems, payers and societies, while interventions including testing and screening policies, vaccination and physical distancing policies were identified as those presenting cost-effective options to deal with the pandemic, dependent on population vaccination and the Re at the stage of the pandemic.

The Impact of Being Homeless on the Clinical Outcomes of COVID-19: Systematic Review

Objective: The homeless population experiences inequality in health compared with the general population, which may have widened during the COVID-19 pandemic. However, the impact of being homeless on the outcomes of COVID-19 is uncertain. This systematic review aimed to analyse the impact of experiencing homelessness on the clinical outcomes of COVID-19, including the effects on health inequalities. Methods: A review protocol was developed and registered in PROSPERO (PROSPERO registration 2022 CRD42022304941). Nine databases were searched in November 2022 to identify studies on homeless populations which contained primary research on the following outcomes of COVID-19: incidence, hospitalisation, mortality, long COVID, mental wellbeing, and evidence of inequalities. Included studies were summarised with narrative synthesis. Results: The searches yielded 8,233 initial hits; after screening, 41 studies were included. Overall, evidence showed that those in crowded living settings had a higher risk of COVID-19 infection compared to rough sleepers and the general population. The homeless population had higher rates of hospitalisation and mortality than the general population, lower vaccination rates, and suffered negative mental health impacts. Conclusion: This systematic review shows the homeless population is more susceptible to COVID-19 outcomes. Further research is needed to determine the actual impact of the pandemic on this population, and of interventions to mitigate overall risk, given the low certainty of findings from some of the low-quality evidence available. In addition, further research is required to ascertain the impact of long COVID on those experiencing homelessness, since the present review yielded no studies on this topic.

Morbidity and mortality in a prospective cohort of people who were homeless during the COVID-19 pandemic

Introduction

Certain living conditions, such as homelessness, increase health risks in epidemic situations. We conducted a prospective observational cohort study to investigate the impact of the COVID-19 pandemic on morbidity and mortality in adult people who were homeless.

Methods

The study population comprised around 40% of the entire population experiencing homelessness in Marseille. They were enrolled at 48 different locations during the first pandemic wave (June to August 2020) and were followed up 3 and 6 months later. Rapid serological screening for SARS-CoV-2 was performed by community outreach teams at each follow-up, who also conducted interviews. Death registers and hospital administrative databases were consulted.

Results

A total of 1,332 participants [mean age 40.1 years [SD 14.2], women 339 (29.9%)] were enrolled in the cohort. Of these, 192 (14.4%) participants were found positive for COVID-19 and were propensity score matched (1:3) and compared with 553 non-COVID-19 cases. Living in emergency shelters was associated with COVID-19 infection. While 56.3% of the COVID-19-infected cohort reported no symptoms, 25.0% were hospitalized due to the severity of the disease. Presence of three or more pre-existing comorbidities was associated with all-cause hospitalization. Among COVID-19 cases, only older age was associated with COVID-19 hospitalization. Three deaths occurred in the cohort, two of which were among the COVID-19 cases.

Conclusion

The study provides new evidence that the population experiencing homelessness faces higher risks of infection and hospitalization due to COVID-19 than the general population. Despite the efforts of public authorities, the health inequities experienced by people who are homeless remained major. More intensive and appropriate integrated care and earlier re-housing are needed.

The economics of the COVID-19 pandemic: economic evaluation of government mitigation and suppression policies, health system innovations, and models of care

Background

The COVID-19 pandemic has impacted the scope of health economics literature, which will increasingly examine value beyond health care interventions such as government policy and broad health system innovations.

Aim

The study analyzes economic evaluations and methodologies evaluating government policies suppressing or mitigating transmission and reducing COVID-19, broad health system innovations, and models of care. This can facilitate future economic evaluations and assist government and public health policy decisions during pandemics.

Methods

The Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) was used. Methodological quality was quantified using the scoring criteria in European Journal of Health Economics, Consolidated Health Economic Evaluation Reporting Standards (CHEERS) 2022 Checklist and the National Institute for Health and Care Excellence's (NICE) Cost Benefit Analysis Checklist. PUBMED, Medline, and Google Scholar were searched from 2020-2021.

Results

Cost utility analysis (CUA) and cost benefit analysis (CBA) analyzing mortality, morbidity, quality adjusted life year (QALY) gained, national income loss, and value of production effectively evaluate government policies suppressing or mitigating COVID-19 transmission, disease, and impacting national income loss. The WHO's pandemic economic framework facilitates economic evaluations of social and movement restrictions. Social return on investment (SROI) links benefits to health and broader social improvements. Multi-criteria decision analysis (MCDA) can facilitate vaccine prioritization, equitable health access, and technology evaluation. Social welfare function (SWF) can account for social inequalities and population-wide policy impact. It is a generalization of CBA, and operationally, it is equal to an equity-weighted CBA. It can provide governments with a guideline for achieving the optimal distribution of income, which is vital during pandemics. Economic evaluations of broad health system innovations and care models addressing COVID-19 effectively use cost effectiveness analysis (CEA) that utilize decision trees and Monte Carlo models, and CUAs that effectively utilize decision trees and Markov models, respectively.

Conclusion

These methodologies are very instructive for governments, in addition to their current use of CBA and the value of a statistical life analytical tool. CUA and CBA effectively evaluate government policies suppressing or mitigating COVID-19 transmission, disease, and impacts on national income loss. CEA and CUA effectively evaluate broad health system innovations and care models addressing COVID-19. The WHO's framework, SROI, MCDA, and SWF can also facilitate government decision-making during pandemics.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10389-023-01919-z.

Cost-Effectiveness Analysis of COVID-19 Inactivated Vaccines in Reducing the Economic Burden of Ischaemic Stroke after SARS-CoV-2 Infection

Due to significant economic burden and disability from ischaemic stroke and the relationship between ischaemic stroke and SARS-CoV-2 infection, we aimed to explore the cost-effectiveness of the two-dose inactivated COVID-19 vaccination program in reducing the economic burden of ischaemic stroke after SARS-CoV-2 infection. We constructed a decision-analytic Markov model to compare the two-dose inactivated COVID-19 vaccination strategy to the no vaccination strategy using cohort simulation. We calculated incremental cost-effectiveness ratios (ICERs) to evaluate the cost-effectiveness and used number of the ischaemic stroke cases after SARS-CoV-2 infection and quality-adjusted life-years (QALYs) to assess effects. Both one-way deterministic sensitivity analysis and probabilistic sensitivity analysis were performed to assess the robustness of the results. We found that the two-dose inactivated vaccination strategy reduced ischaemic stroke cases after SARS-CoV-2 infection by 80.89% (127/157) with a USD 1.09 million as vaccination program cost, saved USD 3675.69 million as direct health care costs and gained 26.56 million QALYs compared with no vaccination strategy among 100,000 COVID-19 patients (ICER < 0 per QALY gained). ICERs remained robust in sensitivity analysis. The proportion of older patients and the proportion of two-dose inactivated vaccination among older people were the critical factors that affected ICER. This study suggests the importance of COVID-19 vaccination is not only in preventing the spread of infectious diseases, but also in considering its long-term value in reducing the economic burden of non-communicable diseases such as ischaemic stroke after SARS-CoV-2 infection.

Cumulative incidence of SARS-CoV-2 infection within the homeless population: insights from a city-wide longitudinal study

OBJECTIVES

The aim of this study was to determine the risk factors associated with SARS-CoV-2 infection in a cohort of homeless people using survival analysis. Seroprevalence in the homeless community was also compared with that of the general population.

DESIGN

Cohort study.

SETTING

Data were collected across two testing sessions, 3 months apart, during which each participant was tested for anti-SARS-CoV-2 antibodies and completed a face-to-face survey.

PARTICIPANTS

All homeless adults sleeping rough, in slums or squats, in emergency shelters or transitional accommodation in Marseille were eligible.

PRIMARY OUTCOME MEASURES

Occurrence of a seroconversion event defined as a biologically confirmed SARS-CoV-2 infection. Local data from a national seroprevalence survey were used for comparison between homeless people and the general population.

RESULTS

A total of 1249 people were included. SARS-CoV-2 seroprevalence increased from 6.0% (4.7-7.3) during the first session to 18.9% (16.0-21.7) during the second one, compared with 3.0% (1.9-4.2) and 6.5% (4.5-8.7) in the general population. Factors significantly associated with an increased risk of COVID-19 infection were: having stayed in emergency shelters (1.93 (1.18-3.15)), being an isolated parent (1.64 (1.07-2.52)) and having contact with more than 5-15 people per day (1.84 (1.27-2.67)). By contrast, smoking (0.46 (0.32-0.65)), having financial resources (0.70 (0.51-0.97)) and psychiatric or addictive comorbidities (0.52 (0.32-0.85)) were associated with a lower risk.

CONCLUSION

We confirm that homeless people have higher infection rates than the general population, with increased risk in emergency shelters. There is growing evidence that, in addition to usual preventive measures, public policies should pay attention to adapt the type of accommodation and overall approach of precariousness.

TRIAL REGISTRATION NUMBER

NCT04408131.

mRNA-based COVID-19 booster vaccination is highly effective and cost-effective in Australia

BACKGROUND

Australia implemented an mRNA-based booster vaccination strategy against the COVID-19 Omicron variant in November 2021. We aimed to evaluate the effectiveness and cost-effectiveness of the booster strategy over 180 days.

METHODS

We developed a decision-analytic Markov model of COVID-19 to evaluate the cost-effectiveness of a booster strategy (administered 3 months after 2nd dose) in those aged ≥ 16 years, from a healthcare system perspective. The willingness-to-pay threshold was chosen as A$ 50,000.

RESULTS

Compared with 2-doses of COVID-19 vaccines without a booster, Australia's booster strategy would incur an additional cost of A$0.88 billion but save A$1.28 billion in direct medical cost and gain 670 quality-adjusted life years (QALYs) in 180 days of its implementation. This suggested the booster strategy is cost-saving, corresponding to a benefit-cost ratio of 1.45 and a net monetary benefit of A$0.43 billion. The strategy would prevent 1.32 million new infections, 65,170 hospitalisations, 6,927 ICU admissions and 1,348 deaths from COVID-19 in 180 days. Further, a universal booster strategy of having all individuals vaccinated with the booster shot immediately once their eligibility is met would have resulted in a gain of 1,599 QALYs, a net monetary benefit of A$1.46 billion and a benefit-cost ratio of 1.95 in 180 days.

CONCLUSION

The COVID-19 booster strategy implemented in Australia is likely to be effective and cost-effective for the Omicron epidemic. Universal booster vaccination would have further improved its effectiveness and cost-effectiveness.

Best practices to reduce COVID-19 in group homes for individuals with serious mental illness and intellectual and developmental disabilities: Protocol for a hybrid type 1 effectiveness-implementation cluster randomized trial

BACKGROUND

People with serious mental illness (SMI) and intellectual disabilities and/or developmental disabilities (ID/DD) living in group homes (GHs) and residential staff are at higher risk for COVID-19 infection, hospitalization, and death compared with the general population.

METHODS

We describe a hybrid type 1 effectiveness-implementation cluster randomized trial to assess evidence-based infection prevention practices to prevent COVID-19 for residents with SMI or ID/DD and the staff in GHs. The trial will use a cluster randomized design in 400 state-funded GHs in Massachusetts for adults with SMI or ID/DD to compare effectiveness and implementation of "Tailored Best Practices" (TBP) consisting of evidence-based COVID-19 infection prevention practices adapted for residents with SMI and ID/DD and GH staff; to "General Best Practices" (GBP), consisting of required standard of care reflecting state and federal standard general guidelines for COVID-19 prevention in GHs. External (i.e., community-based research staff) and internal (i.e., GH staff leadership) personnel will facilitate implementation of TBP. The primary effectiveness outcome is incident SARS-CoV-2 infection and secondary effectiveness outcomes include COVID-19-related hospitalizations and mortality in GHs. The primary implementation outcomes are fidelity to TBP and rates of COVID-19 vaccination. Secondary implementation outcomes are adoption, adaptation, reach, and maintenance. Outcomes will be assessed at baseline, 3-, 6-, 9-, 12-, and 15-months post-randomization.

CONCLUSIONS

This study will advance knowledge on comparative effectiveness and implementation of two different strategies to prevent COVID-19-related infection, morbidity, and mortality and promote fidelity and adoption of these interventions in high-risk GHs for residents with SMI or ID/DD and staff.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04726371.

Respiratory infectious disease outbreaks among people experiencing homelessness: a systematic review of prevention and mitigation strategies

PURPOSE

People experiencing homelessness (PEH) are at increased risk of respiratory infections and associated morbidity and mortality. To characterize optimal intervention strategies, we completed a systematic review of mitigation strategies for PEH to minimize the spread and impact of respiratory infectious disease outbreaks, including COVID-19.

METHODS

The study protocol was registered in PROSPERO (#2020 CRD42020208964) and was consistent with the preferred reporting in systematic reviews and meta-analyses guidelines. A search algorithm containing keywords that were synonymous to the terms "Homeless" and "Respiratory Illness" was applied to the six databases. The search concluded on September 22, 2020. Quality assessment was performed at the study level. Steps were conducted by two independent team members.

RESULTS

A total of 4468 unique titles were retrieved with 21 meeting criteria for inclusion. Interventions included testing, tracking, screening, infection prevention and control, isolation support, and education. Historically, there has been limited study of intervention strategies specifically for PEH across the world.

CONCLUSIONS

Staff and organizations providing services for people experiencing homelessness face specific challenges in adhering to public health guidelines such as physical distancing, isolation, and routine hygiene practices. There is a discrepancy between the burden of infectious diseases among PEH and specific research characterizing optimal intervention strategies to mitigate transmission in the context of shelters. Improving health for people experiencing homelessness necessitates investment in programs scaling existing interventions and research to study new approaches.

Targeting D-Amino Acid Oxidase (DAAO) for the Treatment of Schizophrenia: Rationale and Current Status of Research

In the brain, D-amino acid oxidase (DAAO) is a peroxisomal flavoenzyme. Through oxidative deamination by DAAO, D-serine, the main coagonist of synaptic N-methyl-D-aspartate receptors (NMDARs), is degraded into α-keto acids and ammonia; flavin adenine dinucleotide (FAD) is simultaneously reduced to dihydroflavine-adenine dinucleotide (FADH2), which is subsequently reoxidized to FAD, with hydrogen peroxide produced as a byproduct. NMDAR hypofunction is implicated in the pathogenesis of schizophrenia. In previous studies, compared with control subjects, patients with schizophrenia had lower D-serine levels in peripheral blood and cerebrospinal fluid but higher DAAO expression and activity in the brain. Inhibiting DAAO activity and slowing D-serine degradation by using DAAO inhibitors to enhance NMDAR function may be a new strategy for use in the treatment of schizophrenia. The aim of this leading article is to review the current research in DAAO inhibitors.

Impacts of the COVID-19 pandemic, and of government responses to the pandemic, on people who are homeless in Australia: Mapping perceptions of a national sample of homelessness service workers

People who are homeless are disproportionately impacted by the COVID-19 pandemic, and by government responses to the pandemic. This study maps the perceptions of homelessness service workers in Australia, about the impacts of the COVID-19 pandemic and government responses to it on people who are homeless. An electronic survey was distributed to homelessness service across Australia in June/July 2020, following Australia's 'first wave' of COVID-19. Fifty-nine homelessness services from all eight states/territories responded. Perceptions of impacts on people who are homeless were mapped in six themes: (1) changes in the types of people presenting, (2) overall impacts on peoples' lives, (3) impacts on mental health, (4) impacts of changes in service delivery, (5) impacts of government support and (6) ongoing impacts. The COVID-19 pandemic, and government responses to the pandemic, have affected every aspect of the lives of people who are homeless in Australia. There is a continuing need to support people who are homeless as the world transitions to the 'new normal' of COVID-19, particularly as rates of homelessness increase. Understanding impacts is vital to informing relevant and effective health, social and other supports for this group.

COVID-19 prevalence and infection control measures at homeless shelters and hostels in high-income countries: a scoping review

BACKGROUND

The COVID-19 pandemic has disproportionately impacted homeless populations and service workers, especially within homeless shelter/hostel settings. To date, there have been few evidence syntheses examining outbreaks of COVID-19 among both homeless shelter residents and service workers and no critical review of infection control and prevention (IPAC) measures. This scoping review offers a much-needed synthesis of COVID-19 prevalence within homeless shelters and a review of pertinent IPAC measures.  METHODS: We conducted a scoping review that aimed to synthesize academic and gray literature published from March 2020 to July 2021 pertaining to (1) the prevalence of COVID-19 among both residents and staff in homeless shelters and hostels in high-income countries and (2) COVID-19 IPAC strategies applied in these settings. Two reviewers independently screened the literature from several databases that included MEDLINE, PsycInfo, and the WHO's COVID-19 Global Health Portal. The extracted data was mapped, categorized, and thematically discussed.

RESULTS

Thematic analysis of 77 academic and gray literature documents revealed four key themes: (1) the demographics of COVID-19 in homeless shelters, (2) asymptomatic spread, (3) pre-existing vulnerability of people experiencing homelessness and shelters, and (4) the inconsistency and ineffectiveness of IPAC implementation.

CONCLUSION

This review offers a useful glimpse into the landscape of COVID-19 outbreaks in homeless shelters/hostels and the major contributing factors to these events. This review revealed that there is no clear indication of generally accepted IPAC standards for shelter residents and workers. This review also illustrated a great need for future research to establish IPAC best practices specifically for homeless shelter/hostel contexts. Finally, the findings from this review reaffirm that homelessness prevention is key to limiting disease outbreaks and the associated negative health outcomes in shelter populations. Limitations of this review included the temporal and database constraints of the search strategy, the exclusion of quality assessments of the literature, and the absence of investigation on the influence of emerging variants on public health policy.

SYSTEMATIC REVIEW REGISTRATION

This scoping review has not been registered on any database; the protocol is available on York University's Institutional Repository https://dx.doi.org/10.25071/10315/38513 .

Designing isolation guidelines for COVID-19 patients with rapid antigen tests

Appropriate isolation guidelines for COVID-19 patients are warranted. Currently, isolating for fixed time is adopted in most countries. However, given the variability in viral dynamics between patients, some patients may no longer be infectious by the end of isolation, whereas others may still be infectious. Utilizing viral test results to determine isolation length would minimize both the risk of prematurely ending isolation of infectious patients and the unnecessary individual burden of redundant isolation of noninfectious patients. In this study, we develop a data-driven computational framework to compute the population-level risk and the burden of different isolation guidelines with rapid antigen tests (i.e., lateral flow tests). Here, we show that when the detection limit is higher than the infectiousness threshold values, additional consecutive negative results are needed to ascertain infectiousness status. Further, rapid antigen tests should be designed to have lower detection limits than infectiousness threshold values to minimize the length of prolonged isolation.

Utilizing viral test results to determine isolation length would minimize both the risk of prematurely ending isolation of infectious patients and the unnecessary individual burden of redundant isolation of noninfectious patients. Here, the authors develop a framework to compute the population-level risk of different isolation guidelines with rapid antigen tests.

A Systematic Review of Economic Evaluations of COVID-19 Interventions: Considerations of Non-Health Impacts and Distributional Issues

OBJECTIVES

This study aims to conduct a systematic review of economic evaluations of COVID-19 interventions and to examine whether and how these studies incorporate non-health impacts and distributional concerns.

METHODS

We searched the National Institutes of Health's COVID-19 Portfolio as of May 20, 2021, and supplemented our search with additional sources. We included original articles, including preprints, evaluating both the health and economic effects of a COVID-19-related intervention. Using a pre-specified data collection form, 2 reviewers independently screened, reviewed, and extracted information about the study characteristics, intervention types, and incremental cost-effectiveness ratios (ICERs). We used an Impact Inventory to catalog the types of non-health impacts considered.

RESULTS

We included 70 articles, almost half of which were preprints. Most articles (56%) included at least one non-health impact, but fewer (21%) incorporated non-economic consequences. Few articles (17%) examined subgroups of interest. After excluding negative ICERs, the median ICER for the entire sample (n = 243 ratios) was $67,000/quality-adjusted life-year (QALY) (interquartile range [IQR] $9000-$893,000/QALY). Interventions including a pharmaceutical component yielded a median ICER of $93,000/QALY (IQR $4000-$7,809,000/QALY), whereas interventions including a non-pharmaceutical component were slightly more cost-effective overall with a median ICER of $81,000/QALY (IQR $12,000-$1,034,000/QALY). Interventions reported to be highly cost-effective were treatment, public information campaigns, quarantining identified contacts/cases, canceling public events, and social distancing.

CONCLUSIONS

Our review highlights the lack of consideration of non-health and distributional impacts among COVID-19-related economic evaluations. Accounting for non-health impacts and distributional effects is essential for comprehensive assessment of interventions' value and imperative for generating cost-effectiveness evidence for both current and future pandemics.

The Role of Digital Technology in Curbing COVID-19

Introduction: Using digital technology to provide support, medical consultations, healthcare services, and to track the spread of the coronavirus has been identified as an important solution to curb the transmission of the virus. This research paper aims to (1) summarize the digital technologies used during the COVID-19 pandemic to mitigate the transmission of the COVID-19; (2) establish the extent to which digital technology applications have facilitated mitigation of the spread of COVID-19; and (3) explore the facilitators and barriers that impact the usability of digital technologies throughout the pandemic. Methods: A rapid electronic search following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted of available records up to June 2022 on the medical databases PubMed, Ovid, Embase, CINHAIL, the Cochrane Library, Web of Science, and Google Scholar. Results: An increasing number and variety of digital health applications have been available throughout the pandemic, such as telehealth, smartphone mobile health apps, machine learning, and artificial intelligence. Each technology has played a particular role in curbing COVID-19 transmission. Different users have gained benefits from using digital technology during the COVID-19 pandemic and different determinants have contributed to accelerating the wheel of digital technology implementation during the pandemic. Conclusion: Digital health during the COVID-19 pandemic has evolved very rapidly, with different applications and roles aimed at curbing the pandemic.

Cost-effectiveness of interventions for the prevention and control of COVID-19: Systematic review of 85 modelling studies

Background

We aimed to quantitatively summarise the health economic evaluation evidence of prevention and control programs addressing COVID-19 globally.

Methods

We did a systematic review and meta-analysis to assess the economic and health benefit of interventions for COVID-19. We searched PubMed, Embase, Web of Science, and Cochrane Library of economic evaluation from December 31, 2019, to March 22, 2022, to identify relevant literature. Meta-analyses were done using random-effects models to estimate pooled incremental net benefit (INB). Heterogeneity was assessed using I2 statistics and publication bias was assessed by Egger's test. This study is registered with PROSPERO, CRD42021267475.

Results

Of 16 860 studies identified, 85 articles were included in the systematic review, and 25 articles (10 studies about non-pharmacological interventions (NPIs), five studies about vaccinations and 10 studies about treatments) were included in the meta-analysis. The pooled INB of NPIs, vaccinations, and treatments were $1378.10 (95% CI = $1079.62, $1676.59), $254.80 (95% CI = $169.84, $339.77) and $4115.11 (95% CI = $1631.09, $6599.14), respectively. Sensitivity analyses showed similar findings.

Conclusions

NPIs, vaccinations, and treatments are all cost-effective in combating the COVID-19 pandemic. However, evidence was mostly from high-income and middle-income countries. Further studies from lower-income countries are needed.

COVID-19 in Homelessness: A Worldwide Scoping Review on Vulnerabilities, Risks, and Risk Management

Homeless individuals are at greater risk of death due to social inequalities during Covid-19 pandemic. Strategies taken for general population to prevent the spread of Covid-19, such as social distance, staying at home, and observing personal hygiene are not possible for this group of people. This is a scoping review on articles published and other credible resources published analyze studies done on homeless people during the COVID-19 pandemic. In this scoping review, for the first time, we studied published articles on the situation of the homeless during the Covid-19 epidemic and by extracting and categorizing vulnerabilities, risks, as well as risk management plans, Finally we presented, useful guidance for organizations providing health and social services during the spread of diseases.

Implementation of Baltimore City's COVID-19 Isolation Hotel

In May 2020, Baltimore City, Maryland, implemented the Lord Baltimore Triage, Respite, and Isolation Center (LBTC), a multiagency COVID-19 isolation and quarantine site tailored for people experiencing homelessness. In the first year, 2020 individuals were served, 78% completed isolation at LBTC, and 6% were transferred to a hospital. Successful isolation can mitigate outbreaks in shelters and residential recovery programs, and planning for sustainable isolation services integrated within these settings is critical as the COVID-19 pandemic continues. (Am J Public Health. Published online ahead of print April 21, 2022: e1-e5. https://doi.org/10.2105/AJPH.2022.306778).

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 15^th to February 19^th, 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.

Designing isolation guidelines for COVID-19 patients utilizing rapid antigen tests: a simulation study using viral dynamics models.. [PMID: 35118478 PMCID: PMC8811911 DOI: 10.1101/2022.01.24.22269769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Appropriate isolation guidelines for COVID-19 patients are warranted. Currently, isolating for fixed time is adapted in most countries. However, given the variability in viral dynamics between patients, some patients may no longer be infectious by the end of isolation (thus they are redundantly isolated), whereas others may still be infectious. Utilizing viral test results to determine ending isolation would minimize both the risk of ending isolation of infectious patients and the burden due to redundant isolation of noninfectious patients. In our previous study, we proposed a computational framework using SARS-CoV-2 viral dynamics models to compute the risk and the burden of different isolation guidelines with PCR tests. In this study, we extend the computational framework to design isolation guidelines for COVID-19 patients utilizing rapid antigen tests. Time interval of tests and number of consecutive negative tests to minimize the risk and the burden of isolation were explored. Furthermore, the approach was extended for asymptomatic cases. We found the guideline should be designed considering various factors: the infectiousness threshold values, the detection limit of antigen tests, symptom presence, and an acceptable level of releasing infectious patients. Especially, when detection limit is higher than the infectiousness threshold values, more consecutive negative results are needed to ascertain loss of infectiousness. To control the risk of releasing of infectious individuals under certain levels, rapid antigen tests should be designed to have lower detection limits than infectiousness threshold values to minimize the length of prolonged isolation, and the length of prolonged isolation increases when the detection limit is higher than the infectiousness threshold values, even though the guidelines are optimized for given conditions.

Prevalence of SARS-CoV-2 infection among people experiencing homelessness in Toronto during the first wave of the COVID-19 pandemic

OBJECTIVES

People experiencing homelessness are at increased risk of SARS-CoV-2 infection. This study reports the point prevalence of SARS-CoV-2 infection during testing conducted at sites serving people experiencing homelessness in Toronto during the first wave of the COVID-19 pandemic. We also explored the association between site characteristics and prevalence rates.

METHODS

The study included individuals who were staying at shelters, encampments, COVID-19 physical distancing sites, and drop-in and respite sites and completed outreach-based testing for SARS-CoV-2 during the period April 17 to July 31, 2020. We examined test positivity rates over time and compared them to rates in the general population of Toronto. Negative binomial regression was used to examine the relationship between each shelter-level characteristic and SARS-CoV-2 positivity rates. We also compared the rates across 3 time periods (T1: April 17-April 25; T2: April 26-May 23; T3: May 24-June 25).

RESULTS

The overall prevalence of SARS-CoV-2 infection was 8.5% (394/4657). Site-specific rates showed great heterogeneity with infection rates ranging from 0% to 70.6%. Compared to T1, positivity rates were 0.21 times lower (95% CI: 0.06-0.75) during T2 and 0.14 times lower (95% CI: 0.04-0.44) during T3. Most cases were detected during outbreak testing (384/394 [97.5%]) rather than active case finding.

CONCLUSION

During the first wave of the pandemic, rates of SARS-CoV-2 infection at sites for people experiencing homelessness in Toronto varied significantly over time. The observation of lower rates at certain sites may be attributable to overall time trends, expansion of outreach-based testing to include sites without known outbreaks, and/or individual site characteristics.

Monitoring for COVID-19 by universal testing in a homeless shelter in Germany: a prospective feasibility cohort study

BACKGROUND

Living conditions in homeless shelters facilitate the transmission of COVID-19. Social determinants and pre-existing health conditions place homeless people at increased risk of severe disease. Described outbreaks in homeless shelters resulted in high proportions of infected residents and staff members. In addition to other infection prevention strategies, regular shelter-wide (universal) testing for COVID-19 may be valuable, depending on the level of community transmission and when resources permit.

METHODS

This was a prospective feasibility cohort study to evaluate universal testing for COVID-19 at a homeless shelter with 106 beds in Berlin, Germany. Co-researchers were recruited from the shelter staff. A PCR analysis of saliva or self-collected nasal/oral swab was performed weekly over a period of 3 weeks in July 2020. Acceptability and implementation barriers were analyzed by process evaluation using mixed methods including evaluation sheets, focus group discussion and a structured questionnaire.

RESULTS

Ninety-three out of 124 (75%) residents were approached to participate in the study. Fifty-one out of the 93 residents (54.8%) gave written informed consent; thus 41.1% (51 out of 124) of all residents were included in the study. Among these, high retention rates (88.9-93.6%) of a weekly respiratory specimen were reached, but repeated collection attempts, as well as assistance were required. Around 48 person-hours were necessary for the sample collection including the preparation of materials. A self-collected nasal/oral swab was considered easier and more hygienic to collect than a saliva specimen. No resident was tested positive by RT-PCR. Language barriers were the main reason for non-participation. Flexibility of sample collection schedules, the use of video and audio materials, and concise written information were the main recommendations of the co-researchers for future implementation.

CONCLUSIONS

Voluntary universal testing for COVID-19 is feasible in homeless shelters. Universal testing of high-risk facilities will require flexible approaches, considering the level of the community transmission, the available resources, and the local recommendations. Lack of human resources and laboratory capacity may be a major barrier for implementation of universal testing, requiring adapted approaches compared to standard individual testing. Assisted self-collection of specimens and barrier free communication may facilitate implementation in homeless shelters. Program planning must consider homeless people's needs and life situation, and guarantee confidentiality and autonomy.

Clinical outcomes and cost-effectiveness of COVID-19 vaccination in South Africa

Low- and middle-income countries are implementing COVID-19 vaccination strategies in light of varying vaccine efficacies and costs, supply shortages, and resource constraints. Here, we use a microsimulation model to evaluate clinical outcomes and cost-effectiveness of a COVID-19 vaccination program in South Africa. We varied vaccination coverage, pace, acceptance, effectiveness, and cost as well as epidemic dynamics. Providing vaccines to at least 40% of the population and prioritizing vaccine rollout prevented >9 million infections and >73,000 deaths and reduced costs due to fewer hospitalizations. Model results were most sensitive to assumptions about epidemic growth and prevalence of prior immunity to SARS-CoV-2, though the vaccination program still provided high value and decreased both deaths and health care costs across a wide range of assumptions. Vaccination program implementation factors, including prompt procurement, distribution, and rollout, are likely more influential than characteristics of the vaccine itself in maximizing public health benefits and economic efficiency.

Cost-Effectiveness of COVID-19 Policy Measures: A Systematic Review

OBJECTIVES

The COVID-19 pandemic has had a major impact on our society, with drastic policy restrictions being implemented to contain the spread of the severe acute respiratory syndrome coronavirus 2. This study aimed to provide an overview of the available evidence on the cost-effectiveness of various coronavirus disease 2019 policy measures.

METHODS

A systematic literature search was conducted in PubMed, Embase, and Web of Science. Health economic evaluations considering both costs and outcomes were included. Their quality was comprehensively assessed using the Consensus Health Economic Criteria checklist. Next, the quality of the epidemiological models was evaluated.

RESULTS

A total of 3688 articles were identified (March 2021), of which 23 were included. The studies were heterogeneous with regard to methodological quality, contextual factors, strategies' content, adopted perspective, applied models, and outcomes used. Overall, testing/screening, social distancing, personal protective equipment, quarantine/isolation, and hygienic measures were found to be cost-effective. Furthermore, the most optimal choice and combination of strategies depended on the reproduction number and context. With a rising reproduction number, extending the testing strategy and early implementation of combined multiple restriction measures are most efficient.

CONCLUSIONS

The quality assessment highlighted numerous flaws and limitations in the study approaches; hence, their results should be interpreted with caution because the specific context (country, target group, etc) is a key driver for cost-effectiveness. Finally, including a societal perspective in future evaluations is key because this pandemic has an indirect impact on the onset and treatment of other conditions and on our global economy.

Clinical outcomes and cost-effectiveness of COVID-19 vaccination in South Africa

Low- and middle-income countries are implementing COVID-19 vaccination strategies in light of varying vaccine efficacies and costs, supply shortages, and resource constraints. Here, we use a microsimulation model to evaluate clinical outcomes and cost-effectiveness of a COVID-19 vaccination program in South Africa. We varied vaccination coverage, pace, acceptance, effectiveness, and cost as well as epidemic dynamics. Providing vaccines to at least 40% of the population and prioritizing vaccine rollout prevented >9 million infections and >73,000 deaths and reduced costs due to fewer hospitalizations. Model results were most sensitive to assumptions about epidemic growth and prevalence of prior immunity to SARS-CoV-2, though the vaccination program still provided high value and decreased both deaths and health care costs across a wide range of assumptions. Vaccination program implementation factors, including prompt procurement, distribution, and rollout, are likely more influential than characteristics of the vaccine itself in maximizing public health benefits and economic efficiency.

Cost, supply and logistics present challenges to COVID-19 vaccine rollout in low and middle income countries. Here, the authors model vaccination programmes in South Africa and demonstrate the importance of the pace of vaccine rollout, with even moderately efficacious vaccines likely to be cost-effective.

SARS-Cov-2 prevalence, transmission, health-related outcomes and control strategies in homeless shelters: Systematic review and meta-analysis

BACKGROUND

People experiencing homelessness (PEH) may be at risk for COVID19. We synthesised evidence on SARS-Cov-2 infection, transmission, outcomes of disease, effects of non-pharmaceutical interventions (NPI), and the effectiveness of strategies for infection prevention and control (IPC).

METHODS

Systematic review of articles, indexed in electronic databases (EMBASE, WHO-Covid19, Web of Science), institutional websites and the Norwegian Institute of Public Health's live map of COVID-19 evidence, and published from December 1st, 2019, to March 3rd, 2021. Empirical papers of any study design addressing Covid-19 and health(-related) outcomes in PEH or shelters' staff were included. (PROSPERO-2020-CRD42020187033).

FINDINGS

Of 536 publications, 37 studies were included (two modelling, 31 observational, four qualitative studies). Random-effect meta-analysis yields a baseline SARS-Cov-2 prevalence of 2•32% (95% Confidence-Interval, 95%CI=1•30-3•34) in PEH and 1•55% (95%CI=0•79-2•31) in staff. In outbreaks, the pooled prevalence increases to 31•59% (95%CI=20•48-42•71) in PEH and 14•80% (95%CI=10•73-18•87) in staff. Main IPC strategies were universal rapid testing, expansion of non-congregate housing, and in-shelter measures (bed spacing, limited staff rotation, reduction in number of residents).

INTERPRETATION

32% of PEH and 15% staff are infected during outbreaks of SARS-Cov-2 in homeless shelters. Most studies were conducted in the USA. No studies were found quantifying health-related outcomes of NPI. Overview and evaluation of IPC strategies for PEH, a better understanding of disease transmission, and reliable data on PEH within Covid-19 notification systems are needed. Qualitative studies may serve to voice PEH and shelter staff experiences, and guide future evaluations and IPC strategies.

FUNDING

None.

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.

Clinical and Economic Effects of Widespread Rapid Testing to Decrease SARS-CoV-2 Transmission

BACKGROUND

The value of frequent, rapid testing to reduce community transmission of SARS-CoV-2 is poorly understood.

OBJECTIVE

To define performance standards and predict the clinical, epidemiologic, and economic outcomes of nationwide, home-based antigen testing.

DESIGN

A simple compartmental epidemic model that estimated viral transmission, portrayed disease progression, and forecast resource use, with and without testing.

DATA SOURCES

Parameter values and ranges as informed by Centers for Disease Control and Prevention guidance and published literature.

TARGET POPULATION

U.S. population.

TIME HORIZON

60 days.

PERSPECTIVE

Societal; costs included testing, inpatient care, and lost workdays.

INTERVENTION

Home-based SARS-CoV-2 antigen testing.

OUTCOME MEASURES

Cumulative infections and deaths, number of persons isolated and hospitalized, and total costs.

RESULTS OF BASE-CASE ANALYSIS

Without a testing intervention, the model anticipates 11.6 million infections, 119 000 deaths, and $10.1 billion in costs ($6.5 billion in inpatient care and $3.5 billion in lost productivity) over a 60-day horizon. Weekly availability of testing would avert 2.8 million infections and 15 700 deaths, increasing costs by $22.3 billion. Lower inpatient outlays ($5.9 billion) would partially offset additional testing expenditures ($12.5 billion) and workdays lost ($14.0 billion), yielding incremental cost-effectiveness ratios of $7890 per infection averted and $1 430 000 per death averted.

RESULTS OF SENSITIVITY ANALYSIS

Outcome estimates vary widely under different behavioral assumptions and testing frequencies. However, key findings persist across all scenarios, with large reductions in infections, mortality, and hospitalizations. Costs per death averted are roughly an order of magnitude lower than commonly accepted willingness-to-pay values per statistical life saved ($5 to $17 million).

LIMITATIONS

Analysis was restricted to at-home testing. There are uncertainties concerning test performance.

CONCLUSION

High-frequency home testing for SARS-CoV-2 with an inexpensive, imperfect test could contribute to pandemic control at justifiable cost and warrants consideration as part of a national containment strategy.

PRIMARY FUNDING SOURCE

National Institutes of Health.

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.