Assessment of contact tracing for COVID-19 among people experiencing homelessness, Salt Lake County Health Department, March-May 2020.

PURPOSE: Contact tracing is intended to reduce the spread of coronavirus disease 2019 (COVID-19), but it is difficult to conduct among people who live in congregate settings, including people experiencing homelessness (PEH). This analysis compares person-based contact tracing among two populations in Salt Lake County, Utah, from March-May 2020. METHODS: All laboratory-confirmed positive cases among PEH (n = 169) and documented in Utah's surveillance system were included in this analysis. The general population comparison group (n = 163) were systematically selected from all laboratory-confirmed cases identified during the same period. RESULTS: Ninety-three PEH cases (55%) were interviewed compared to 163 (100%) cases among the general population (P < .0001). PEH were more likely to be lost to follow-up at end of isolation (14.2%) versus the general population (0%; P-value < .0001) and provided fewer contacts per case (0.3) than the general population (4.7) (P-value < .0001). Contacts of PEH were more often unreachable (13.0% vs. 7.1%; P-value < .0001). CONCLUSIONS: These findings suggest that contact tracing among PEH should include a location-based approach, along with a person-based approach when resources allow, due to challenges in identifying, locating, and reaching cases among PEH and their contacts through person-based contact tracing efforts alone.

The health-system benefits and cost-effectiveness of using Mycobacterium tuberculosis direct nucleic acid amplification testing to diagnose tuberculosis disease in the United States.

BACKGROUND: The utility of Mycobacterium tuberculosis direct nucleic acid amplification testing (MTD) for pulmonary tuberculosis disease diagnosis in the United States has not been well described. METHODS: We analyzed a retrospective cohort of reported patients with suspected active pulmonary tuberculosis in 2008-2010 from Georgia, Hawaii, Maryland, and Massachusetts to assess MTD use, effectiveness, health-system benefits, and cost-effectiveness. RESULTS: Among 2140 patients in whom pulmonary tuberculosis was suspected, 799 (37%) were M. tuberculosis-culture-positive. Eighty percent (680/848) of patients having acid-fast-bacilli-smear-positive specimens had MTD performed; MTD positive-predictive value (PPV) was 98% and negative-predictive value (NPV) was 94%. Nineteen percent (240/1292) of patients having smear-negative specimens had MTD; MTD PPV was 90% and NPV was 88%. Among patients suspected of tuberculosis but not having MTD, smear PPV for lab-confirmed tuberculosis was 77% and NPV 78%. Compared with no MTD, MTD significantly decreased time to diagnosis in patients with smear-positive/MTD-positive specimens, decreased respiratory isolation for patients having smear-positive/MTD-negative/culture-negative specimens, decreased outpatient days of unnecessary tuberculosis medications, and reduced resources expended on contact investigation. While MTD generally cost more than no MTD, incremental cost savings occurred in patients with human immunodeficiency virus (HIV) or homelessness to diagnose or to exclude tuberculosis, and in patients with substance abuse having smear-negative specimens to exclude tuberculosis. CONCLUSIONS: MTD improved diagnostic accuracy and timeliness and reduced unnecessary respiratory isolation, treatment, and contact investigations. It was cost saving in patients with HIV, homelessness, or substance abuse, but not in others.