Strong Community–Public Health Partnerships May Help Us Move Closer to Tuberculosis Elimination

Persons experiencing homelessness face substantial barriers to care. Food and financial insecurities, limited transportation, and multiple comorbidities are major challenges. These barriers, combined with sleeping in crowded homeless shelters, create a perfect storm for tuberculosis (TB). Despite today’s historically low TB rates, persons experiencing homelessness have an unacceptably 10-fold higher rate of TB than in the US population and are overrepresented in TB outbreaks. An estimated 1.42 million persons (0.4% of the national population) experienced homelessness in 2017, but more than a third of 21 TB outbreaks investigated by the Centers for Disease Control and Prevention from 2009 to 2015 involved overnight homeless shelters. Persons experiencing homelessness accounted for 45% of 457 persons identified with TB in these outbreaks.¹

From 2008 to 2015, persons experiencing homelessness in Fulton County, Georgia, were heavily affected by an outbreak, with 110 cases of isoniazid-resistant TB.^2,3 Fulton County began a mandatory targeted testing program for persons experiencing homelessness as well as community outreach to improve access to TB prevention services.³

DEFINING THE CARE CONTINUUM AND TESTING GAPS

In this issue of AJPH, Collins et al. (p. 1028) describe the cascade of care for TB prevention by treatment of latent TB infection in persons experiencing homelessness in Fulton County from May 2015 through April 2017. The authors compare the effect of two different screening strategies on downstream losses in the care continuum. After identifying patients at risk, the next step in the continuum is offering testing to those who are at risk for infection. If this step falters, it will create a ripple effect downstream in the continuum of care.⁴ In summary, if patients do not have access to testing that they are able to fully use, they will never have the opportunity to complete treatment. Thus, testing is one of the most critical steps in the continuum of care.

To ensure that persons experiencing homelessness have access to TB prevention services, public health programs must ensure a patient-centered approach to testing for TB. The biggest limitation of tuberculin skin testing is that it requires patients to have an initial encounter to place the test and a follow-up to have it read, potentially doubling the barriers to care. Even when the test is performed on-site, with the health care worker performing testing and reading at the same location, returning for the reading at a specific time still may be challenging.

The TB screening of persons experiencing homelessness in Fulton County began both at the health department and within community shelters; tuberculin skin test (TST) was used for the first two years. Thereafter, screening took place with an interferon-γ release assay, QuantiFERON-TB Gold In-Tube (QFT; QIAGEN Inc, Germantown, MD). Use of QFT allowed for TB testing in one visit, with patients receiving their results at their convenience. Fulton County tested an impressive number of individuals with both TST and QFT and offered support to participants in the form of a $5 gift card and transportation.

INTERVENTIONS TO IMPROVE TESTING

The article by Collins et al. provides a cascade analysis of testing strategies used by Fulton County. They found more positive test results with QFT compared with TST, which was largely attributable to decreased return rates. Among those with valid test results, no difference in positivity rates was found. The return rate for those who had a TST placed in clinic was higher than that for those who had a TST placed at the shelter. This could reflect better resources available to those who were able to make it to clinic initially or more favorable testing times or readings compared with on-site testing and likely was not a reflection of differences in test performance.

CHANGING THE TESTING STRATEGY IS NOT ENOUGH

Once patients received a diagnosis of latent TB infection, their ability to move through the care continuum was also different when comparing TST with QFT. Individuals who received TST at the community shelter site had the lowest proportion of accepting and starting treatment, with only 25.4% completing treatment. Lost to follow-up was a major reason for patients not completing latent TB infection treatment. The effect of these losses in the context of the outbreak in Fulton County was significant, and at least one individual who was identified as having active TB missed the TST reading. Just one person with active TB who spends time in a community shelter can lead to unraveling of prevention efforts, fueling an ongoing outbreak in the community.²

PATIENT-CENTERED APPROACH TO PUBLIC HEALTH

The Fulton County TB Program should be applauded for their efforts in identifying a patient-centered approach to care that aligns well with sound public health practice. Another example of providing a patient-centered approach to testing and treating patients at risk for TB includes the approach taken by the Pioneer Square Clinic, a primary care clinic for persons experiencing homelessness in King County, Seattle, Washington.⁵ Feedback from patients indicated that their approach showed an understanding of the challenges that persons experiencing homelessness face, and the efforts to mitigate some of those challenges were well received.

FUTURE ELIMINATION STRATEGIES

Once the outbreaks are over, what is the next step? Should TB prevention services specifically tailored for persons experiencing homelessness continue, and should testing be mandatory for entrance into a shelter? Alternatively, should testing remain in the hands of primary care providers as recommended by the US Preventive Services Task Force in 2016? Mandatory testing programs implemented in shelters, even those that use TST, have been associated with a decrease in TB transmission in community shelters.⁶ However, mandatory testing programs can have unintended consequences, with patients who have not yet been tested being turned away from community shelters, leaving them without shelter for that period. During intervals when incidence is very low among persons experiencing homelessness, the adverse effects of lack of shelter on the individual patient outweigh the risk of TB within the community. In an attempt to mitigate this consequence, some programs will allow entry into a homeless shelter with testing occurring shortly after arrival. Patients with symptoms consistent with TB should be referred for urgent clinical evaluation or, if resources allow, be placed in a separate location. The health department testing of persons experiencing homelessness was discontinued following an outbreak in King County and was replaced by strong community-based programs that provided TB prevention services, including treatment of latent TB infection.⁵ Importantly, the number of persons experiencing homelessness with active TB has decreased to the lowest levels in decades with this transition in King County (M. Narita, MD, personal communication, April 2019). One of the key factors in the expansion of TB prevention services by the Pioneer Square Clinic in Seattle was increased health insurance coverage through the Medicaid expansion.⁵ Second, the local community became very invested in supporting TB expansion services and contributing to mitigating food and clothing insecurities. Ideally, patients would receive the full range of prevention services in their medical home with public health programs shifting to a supportive and consultative role. An approach such as this, if fully implemented, has the potential to obviate the need for testing in response to an outbreak because TB prevention will become part of routine primary care.

As the Fulton County TB Program and Gupta et al.⁵ in collaboration with King County have shown, patient-centered care aligns well with the goals of public health. Putting patients first and ensuring adequate resources and funding for TB prevention, including strong community–public health partnerships, not only will improve individual patient outcomes but also will help us move closer to TB elimination.