Counting the homeless: a previously incalculable tuberculosis risk and its social determinants

Infectious Diseases Among People Experiencing Homelessness: A Systematic Review of the Literature in the United States and Canada, 2003-2022

Homelessness increases the risk of acquiring an infectious disease. We conducted a systematic review of the literature to identify quantitative data related to infectious diseases and homelessness. We searched Google Scholar, PubMed, and SCOPUS for quantitative literature published from January 2003 through December 2022 in English from the United States and Canada. We excluded literature on vaccine-preventable diseases and HIV because these diseases were recently reviewed. Of the 250 articles that met inclusion criteria, more than half were on hepatitis C virus or Mycobacterium tuberculosis. Other articles were on COVID-19, respiratory syncytial virus, Staphylococcus aureus, group A Streptococcus, mpox (formerly monkeypox), 5 sexually transmitted infections, and gastrointestinal or vectorborne pathogens. Most studies showed higher prevalence, incidence, or measures of risk for infectious diseases among people experiencing homelessness as compared with people who are housed or the general population. Although having increased published data that quantify the infectious disease risks of homelessness is encouraging, many pathogens that are known to affect people globally who are not housed have not been evaluated in the United States or Canada. Future studies should focus on additional pathogens and factors leading to a disproportionately high incidence and prevalence of infectious diseases among people experiencing homelessness.

Unsheltered Homelessness and Health: A Literature Review

Context

In recent years, cities across the world have seen widespread growth in unsheltered homelessness, in which a person sleeps in a place not meant for human habitation such as cars, parks, sidewalks, and abandoned buildings. It is widely understood that people experiencing homelessness have poorer health outcomes than the general population. Less is known about the health of people who are unsheltered, yet they may be exposed to greater health risks than their sheltered counterparts. The purpose of this literature review is to evaluate and summarize the evidence on unsheltered homelessness and health.

Evidence Acquisition

A literature search was conducted using PubMed to identify publications on unsheltered homelessness and health. A total of 42 studies were included for review.

Evidence Synthesis

Unsheltered populations experience higher rates of chronic disease, serious mental illness, and substance abuse than sheltered populations. Unsheltered homelessness is strongly associated with chronic homelessness that exacerbates serious mental illness and substance use, which is often co-occurring. Despite having large unmet health needs, unsheltered populations have lower healthcare utilization and often lack health insurance.

Conclusions

Evaluating the impact of shelter status on health outcomes has important implications for the allocation of housing and health services. Longitudinal studies are needed to examine the relationship between the duration of sheltered and unsheltered homelessness and health outcomes and explore the mediating mechanisms that lead to poor health among unsheltered populations. Despite these limitations, our results also suggest an urgent need to address the unique and severe challenges facing unsheltered populations and the need for intervention approaches that are sensitive to these unique disease burdens.

Inadequate housing and pulmonary tuberculosis: a systematic review

Background

Tuberculosis (TB) is a global health issue that has long threatened and continues to threaten human health. While previous studies are important in the search for a cure for TB, to eradicate the disease it is also crucial to analyze environmental influences. Therefore, this study determined the potential effect of inadequate housing on TB and the magnitude of the effect.

Methods

This is a systematic review of the effects of inadequate housing on TB. Between Jan 1, 2011 and Oct 25, 2020, we searched four electronic databases using the search terms “housing AND tuberculosis” or “housing AND TB”. The target population comprised residents of inadequate housing and the homeless.

Results

We found 26 eligible studies. The distribution of the studies across continents was uneven, and the housing issues of interest seemed to vary depending on the economic level of the country. The eight steps identified in TB development and the consequences thereof were more strongly associated with housing affordability than with housing quality.

Conclusions

This is the first systematic review to identify the effects of inadequate housing on TB and to categorize inadequate-housing-related exposure to TB in terms of affordability and quality. The steps identified in TB development and the consequences thereof had a greater association with housing affordability than with housing quality. Therefore, public health interventions regarding housing affordability could be more diverse, and interventions that support affordable housing for residents of inadequate housing and the homeless should proceed simultaneously to improve housing quality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12879-6.

Vulnerable populations and tuberculosis treatment outcomes in Brazil

This article aims to assess the association between being a prisoner or homeless and treatment failure in cases of tuberculosis diagnosed in Brazil in 2015. We examined cases of tuberculosis in prisoners and the homeless in Brazil in 2015 reported to the national notifiable diseases information system using descriptive analysis and logistic regression. There were 82,056 cases of tuberculosis in 2015. Of these, 7,462 (10.3%) were prisoners and 2,782 (3.9%) were homeless. The rate of treatment success in prisoners was 78.6%, while the rate of failure in the homeless was 63.2%. Being a prisoner was a protective factor against treatment failure (adjusted odds ratio 0.68, 95%CI 0.63-0.73), while being homeless was a risk factor for treatment failure (adjusted odds ratio 2.38, 95%CI 2.17-2.61). Treatment success and failure rates differed between prisoners and the homeless. Our findings reinforce the need for public health policies tailored to the specific needs of these groups implemented in conjunction with social services and public security agencies in order to have a significant impact on TB incidence.

Tuberculosis in the street population: a systematic review

OBJECTIVE

To analyze evidence of the occurrence of tuberculosis in people living on the streets provided by the literature.

METHOD

Systematic review conducted in the databases PubMed, EMBASE, LILACS, and SciELO electronic library. Analysis of the empirical material was guided by Hermeneutics. The main themes which give shape to the association between tuberculosis and street population were sought to be understood.

RESULTS

Initially, 343 articles were identified, but only seven met the eligibility criteria. The literature shows that homeless people with tuberculosis presented unfavorable treatment outcomes when compared to the population with fixed residence. Some of the associated reasons were abusive consumption of alcohol and other drugs and associated diseases, such as human immunodeficiency virus and others.

CONCLUSION

Despite the importance of this theme, analysis of the scientific production has provided evidence of the need for studies aimed not only at comprehending the occurrence of disease in this vulnerable group, but specially ways of fighting it.

Treating latent tuberculosis infection (LTBI) with isoniazid and rifapentine (3HP) in an inner-city population with psychosocial barriers to treatment adherence: A qualitative descriptive study

In Canada, preventive therapy for latent tuberculosis infection (LTBI) has required multiple doses of medication over an extended period of time. Such regimens are associated with poor adherence and completion rates. A shortened treatment regimen of once weekly isoniazid plus rifapentine for 3 months (3HP), is now available, and holds promise in populations facing challenges to treatment adherence. Although many factors impact treatment adherence, a knowledge gap exists in describing these factors in the context of this regimen. We present findings from a qualitative descriptive study, involving semi-structured interviews with unstably housed or homeless individuals in Edmonton and Fort McMurray, Alberta, Canada who were offered directly-observed preventive therapy (DOPT) with 3HP, and their health care providers. Latent content analysis revealed incomplete understandings of LTBI and about the need for preventive therapy. Clients' motivation to be healthy, alongside education, health care outreach, relationships developed in the context of DOPT, ease of treatment regimen, incentives, and collaboration were all described as supporting treatment completion. Competing priorities, difficulty in reaching clients, undesirable aspects of the regimen and difficulties obtaining and initiating 3HP were identified as barriers. Perceptions of stigma related to LTBI and TB were described by clients in addition to feelings of shame related to their diagnosis. Our study provides insight into LTBI and indicates that multiple interacting psychosocial factors influence preventive therapy access, uptake, and adherence. Findings from this study of both client and provider perspectives can be used to inform and address inequities among individuals experiencing homelessness, and ultimately contribute to a diminished reservoir of LTBI.

Integrating Social Determinants of Health and Laboratory Data: A Pilot Study To Evaluate Co-Use of Opioids and Benzodiazepines

As the opioid crisis continues to have devastating consequences for our communities, families, and patients, innovative approaches are necessary to augment clinical care and the management of patients with opioid use disorders. As stewards of health analytic data, laboratories are uniquely poised to approach the opioid crisis differently. With this pilot study, we aimed to bridge laboratory data with social determinants of health data, which are known to influence morbidity and mortality of patients with substance use disorders. For the purpose of this pilot study, we focused on the co-use of opioids and benzodiazepines, which can lead to an increased risk of fatal opioid-related overdoses and increased utilization of acute care. Using the laboratory finding of the copresence of benzodiazepines and opioids as the primary outcome measure, we examined social determinants of health attributes that predict co-use. We found that the provider practice that ordered the laboratory result is the primary predictor of co-use. Increasing age was also predictive of co-use. Further, co-use is highly prevalent in specific geographic areas or “hotspots.” The prominent geographic distribution of co-use suggests that targeted educational initiatives may benefit the communities in which co-use is prevalent. This study exemplifies the Clinical Lab 2.0 approach by leveraging laboratory data to gain insights into the overall health of the patient.

Homelessness and Mortality Among Persons With Tuberculosis in Texas, 2010-2017

OBJECTIVE

A disproportionate number of tuberculosis cases and tuberculosis deaths occur among persons experiencing homelessness in the United States. Our objective was to identify risks for homelessness and death during mycobacterial treatment among persons experiencing homelessness with tuberculosis in Texas.

METHODS

Using data from the Centers for Disease Control and Prevention's TB Genotyping Information Management System, we evaluated data on demographic, laboratory, and clinical characteristics of persons experiencing homelessness in Texas during the year before tuberculosis diagnosis, from January 1, 2010, through December 31, 2017.

RESULTS

Of 10 130 new diagnoses of tuberculosis among persons living in Texas during the study period, 543 were reported as being homeless in the year before tuberculosis diagnosis. The odds of dying during treatment were 2.26 (95% confidence interval, 1.68-3.03) times higher among persons with tuberculosis experiencing homelessness than among persons with tuberculosis living in homes.

CONCLUSIONS

Our findings indicate that persons experiencing homelessness bear an undue burden of tuberculosis mortality in Texas. The burden may be related to poorer health caused by poverty stressors, comorbidities, or lack of access to health care.

QuantiFERON-TB Gold Versus Tuberculin Screening and Care Retention Among Persons Experiencing Homelessness: Georgia, 2015-2017

Objectives. To characterize the cascade of care for latent tuberculosis infection (LTBI) in persons experiencing homelessness (PEH) and evaluate the effect of screening by QuantiFERON-TB Gold (QFT) versus tuberculin skin test (TST). Methods. We performed a retrospective cohort study of all PEH screened for LTBI by QFT and TST from May 2015 to April 2017 in Fulton County, Georgia. Results. There were 3504 PEH screened by QFT and 5509 by TST, with 2925 TSTs administered on site at community shelters and 2584 at the health department. More valid test results were obtained in those screened by QFT (99.0% vs 69.0%; P < .001) because of low return rates for reading in both TST arms. For tests administered on site, testing by QFT versus TST improved retention in care with significantly more estimated LTBI cases following up for a medical examination (67.8% vs 51.0%; P < .001) and starting LTBI treatment (58.4% vs 39.8%; P < .001). Conclusions. A QFT-based screening strategy in PEH improved diagnosis and retention in care for new LTBI cases compared with TST and may be an effective strategy to limit progression to active tuberculosis.

Tuberculosis control from the perspective of health professionals working in street clinics

PURPOSE

to present the opinion of professionals about street dwellers undergoing treatment of tuberculosis and identify strategies of control of tuberculosis in this population.

METHOD

an exploratory and descriptive study involving 17 health professionals working in street clinics. A semi-structured study composed of closed questions and a guiding question. The statements were analyzed using the discourse analysis technique, resulting in the identification of two analytical categories: 1. Meanings attributed to street dwellers with tuberculosis, and 2. Control of tuberculosis in homeless people.

RESULTS

the analysis identified situations that limited adherence to tuberculosis treatment, including the reasons for staying in the streets, living conditions, and risk factors (dependence on alcohol and other drugs, short-sightedness, constant relocations, and lack of perspectives). Street dwellers were knowledgeable about the disease. Furthermore, there were difficulties in solving several problems of people living in the streets, including living conditions and lifestyle, social stigma, relocations, drug abuse, and lack of life project.

CONCLUSION

coping with the complexity of situations related to living in the streets limits to the work of health professionals because these situations go beyond health care and require intersectoral actions.

Whole transcriptomic and proteomic analyses of an isogenic M. tuberculosis clinical strain with a naturally occurring 15 Kb genomic deletion

Tuberculosis remains one of the most difficult to control infectious diseases in the world. Many different factors contribute to the complexity of this disease. These include the ability of the host to control the infection which may directly relate to nutritional status, presence of co-morbidities and genetic predisposition. Pathogen factors, in particular the ability of different Mycobacterium tuberculosis strains to respond to the harsh environment of the host granuloma, which includes low oxygen and nutrient availability and the presence of damaging radical oxygen and nitrogen species, also play an important role in the success of different strains to cause disease. In this study we evaluated the impact of a naturally occurring 12 gene 15 Kb genomic deletion on the physiology and virulence of M. tuberculosis. The strains denominated ON-A WT (wild type) and ON-A NM (natural mutant) were isolated from a previously reported TB outbreak in an inner city under-housed population in Toronto, Canada. Here we subjected these isogenic strains to transcriptomic (via RNA-seq) and proteomic analyses and identified several gene clusters with differential expression in the natural mutant, including the DosR regulon and the molybdenum cofactor biosynthesis genes, both of which were found in lower abundance in the natural mutant. We also demonstrated lesser virulence of the natural mutant in the guinea pig animal model. Overall, our findings suggest that the ON-A natural mutant is less fit to cause disease, but nevertheless has the potential to cause extended transmission in at-risk populations.

Experience of health professionals in care of the homeless population with tuberculosis

Abstract OBJECTIVE Analyzing statements of health professionals from a Street Clinic regarding care of a homeless population with tuberculosis. METHOD This is a qualitative research, conducted in the central region of São Paulo at three basic health units in the period of November to December 2014. A semi-structured interview guideline was implemented for data collection and all interviews were recorded using a digital recorder. RESULTS Six health professionals were interviewed. According to the Discourse Analysis perspective, three discursive segments emerged: experiences on care in the streets; weaknesses inherent to the treatment process; and incentives as a means of maintaining sick people in treatment. CONCLUSION Caring for a the homeless population with tuberculosis constitutes a new and challenging experience. It involves difficulties in dealing with the reality of a miserable social context, a lack and inadequacy of services, as well as care limitations for treatment and treatment dropout, which reinforces multiresistance. However, the investigated Street Clinic teams seek to expand access to health and social care services to this population.

Tuberculosis in native Israeli Arabs and Jews: trends and treatment outcomes, 1999-2011

The incidence of tuberculosis (TB) in native ethnic minorities remains high in developed countries. Arabs, the major ethnic minority in Israel, comprise 21% of its population. This retrospective study compared TB incidence, demographic, clinical, laboratory, genotyping characteristics and treatment outcomes in all Israeli-born citizens diagnosed with TB between 1999 and 2011 by ethnicity, i.e. Israeli-born Arabs (IA) and Jews (IJ). A total of 831 Israeli-born TB patients were reported. Of those, there were 530 (64%) IJ and 301 (36%) IA, with an average annual TB rate of 1·1 and 1·6 cases/100 000 population, respectively, lower than the national average (7·0 cases/100 000 population). TB rates in IA and IJ declined and converged to 1 case/100 000 residents. IA TB patients were more likely to be older, have more pulmonary TB and have lower treatment success rates than IJ. Older age and HIV co-infection, but not ethnicity, were predictive of non-success in TB treatment. Ten mixed IA-IJ clades were detected by spoligotyping and three mixed IA-IJ clusters were identified by MIRU-VNTR typing. Only one IA-IJ couple recalled mutual contact. In conclusion, TB rate in IA was higher than in IJ, but declined and converged in both to 1 case/100 000. Treatment success was high in both groups, and was unrelated to ethnicity.

Marked microevolution of a unique Mycobacterium tuberculosis strain in 17 years of ongoing transmission in a high risk population

The transmission and persistence of Mycobacterium tuberculosis within high risk populations is a threat to tuberculosis (TB) control. In the current study, we used whole genome sequencing (WGS) to decipher the transmission dynamics and microevolution of M. tuberculosis ON-A, an endemic strain responsible for an ongoing outbreak of TB in an urban homeless/under-housed population. Sixty-one M. tuberculosis isolates representing 57 TB cases from 1997 to 2013 were subjected to WGS. Sequencing data was integrated with available epidemiological information and analyzed to determine how the M. tuberculosis ON-A strain has evolved during almost two decades of active transmission. WGS offers higher discriminatory power than traditional genotyping techniques, dividing the M. tuberculosis ON-A strain into 6 sub-clusters, each defined by unique single nucleotide polymorphism profiles. One sub-cluster, designated ON-A^NM (Natural Mutant; 26 isolates from 24 cases) was also defined by a large, 15 kb genomic deletion. WGS analysis reveals the existence of multiple transmission chains within the same population/setting. Our results help validate the utility of WGS as a powerful tool for identifying genomic changes and adaptation of M. tuberculosis.

Evaluation of large genotypic Mycobacterium tuberculosis clusters: contributions from remote and recent transmission

Tuberculosis genotypic clustering is used as a proxy for recent transmission. The association between clustering and recent transmission becomes problematic when the genotyping method lacks specificity in defining a cluster, as well as for clusters with extensive jurisdictional histories and/or common genotypes. We investigated the four largest spoligotype/12 loci MIRU-VNTR-defined clusters in Harris County, Texas from 2006-2012 to determine their historical contribution to tuberculosis morbidity, estimate the contributions from recent and remote transmission, and determine the impact of secondary genotyping on cluster definition. The clusters contained 189, 64, 51 and 38 cases. Each cluster was linked to cluster(s) previously identified by Houston Tuberculosis Initiative; 3 since 1995 and the fourth in 2002. Among cases for which timing of Mycobacterium tuberculosis transmission relative to tuberculosis disease could be ascertained, nearly equal proportions were associated with recent and remote transmission. The extent to which genotyping with an additional 12 MIRU-VNTR loci modified the cluster definition varied from little or no impact for the two smaller clusters to moderate impact for the larger clusters. Tuberculosis control measures to reduce morbidity associated with large clusters must involve strategies to identify and treat individuals who recently acquired infection, as well as persons infected for years.