Viral blood-borne infections testing and linkage to care cascade among persons who experience homelessness in the United States: a systematic review and meta-analysis

Background

Persons who experience homelessness remain at increased risk for three viral blood-borne infections: human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). We assessed the yield of testing and linkage to care programs targeting this population for these infections in the United States (US).

Methods

We searched PubMed, Embase, Web of Science, and Cochrane Central for peer-reviewed articles through August 27, 2020. Additionally, we searched the grey literature. Two individuals independently reviewed all relevant studies to check for eligibility and extracted data for each step in the care cascade. We used random-effects model to generate weighted pooled proportions to assess yield at each step. Cumulative proportions were calculated as products of adjacent-step pooled proportions. We quantitatively synthesized data from the studies that focused on non-drug injecting individuals.

Results

We identified 24 studies published between 1996–2019 conducted in 19 US states. Seventeen studies screened for HIV, 12 for HCV, and two screened for HBV. For HIV, 72% of approached were recruited, 64% had valid results, 4% tested positive, 2% were given results, and 1% were referred and attended follow-up. Of positives, 25% were referred to treatment and started care. For HCV, 69% of approached were recruited, 63% had valid results, 16% tested positive, 14% were given results, and 3% attended follow-up. Of positives, 30% were referred for treatment and 19% started care. The yield at each care cascade step differs widely by recruitment strategy (for example, for HIV: 71.6% recruited of reached under service-based with zero yield under healthcare facility-based and outreach).

Conclusions

A very large proportion of this population reached for HIV and HCV care were lost in the follow-up steps and never received treatment. Future programs should examine drop-out reasons and intervene to reduce health disparities in this population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13786-6.

High-Throughput Adaptable SARS-CoV-2 Screening for Rapid Identification of Dominant and Emerging Regional Variants

OBJECTIVES

Emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant strains can be associated with increased transmissibility, more severe disease, and reduced effectiveness of treatments. To improve the availability of regional variant surveillance, we describe a variant genotyping system that is rapid, accurate, adaptable, and able to detect new low-level variants built with existing hospital infrastructure.

METHODS

We used a tiered high-throughput SARS-CoV-2 screening program to characterize variants in a supraregional health system over 76 days. Combining targeted reverse transcription-polymerase chain reaction (RT-PCR) and selective sequencing, we screened SARS-CoV-2 reactive samples from all hospitals within our health care system for genotyping dominant and emerging variants.

RESULTS

The median turnaround for genotyping was 2 days using the high-throughput RT-PCR-based screen, allowing us to rapidly characterize the emerging Delta variant. In our population, the Delta variant is associated with a lower cycle threshold value, lower age at infection, and increased vaccine-breakthrough cases. Detection of low-level and potentially emerging variants highlights the utility of a tiered approach.

CONCLUSIONS

These findings underscore the need for fast, low-cost, high-throughput monitoring of regional viral sequences as the pandemic unfolds and the emergence of SARS-CoV-2 variants increases. Combining RT-PCR-based screening with selective sequencing allows for rapid genotyping of variants and dynamic system improvement.

Routine HIV testing program in the University Infectious Diseases Centre in Lithuania: a four-year analysis

BACKGROUND

HIV transmission remains a major concern in Eastern Europe, and too many people are diagnosed late. Expanded testing strategies and early and appropriate access to care are required. Infectious disease departments might be targets for expanded HIV testing owing to the intense passage of key patient populations that carry indicators of HIV disease. Our objective was to evaluate the feasibility and clinical effectiveness of a fully integrated, opt-out routine, rapid HIV testing program.

METHODS

A retrospective four-year study of a screening program was conducted from 2010 through 2014. The program was divided into two periods: from 2010 to 2012 (pilot study) and from 2013 to 2014. The pilot study consisted of routine HIV testing of patients aged 18-55 that were hospitalized in one department. In the second period, all inpatients aged 18-65 were eligible. Targeted testing was conducted in the other inpatient department during the pilot study and the outpatient department during both periods.

RESULTS

During the pilot study, 2203 patients were hospitalized, 1314 (59.6%) were eligible, 954 (72.6%) were tested, and 3 (0.31%) were newly diagnosed HIV-positive. In the second period, 4911 patients were hospitalized, 3727 (75.9%) were eligible, 3303 (88.6%) were tested, and 7 (0.21%) were HIV-positive. In total, 2800 targeted tests were performed, and 4 (0.14%) patients tested positive with newly discovered HIV. All 14 newly diagnosed patients were provided with care. Comparing cumulative groups of routine and targeted testing, the HIV prevalence was 0.23% vs. 0.14% (p = 0.40) and was above the reported cost-effectiveness threshold of 0.1% (p = 0.012). A lower proportion of advanced disease and a higher proportion of heterosexually transmitted infection were found in the routine testing group.

CONCLUSION

Routine HIV testing in admissions of infectious diseases is acceptable, feasible, sustainable and clinically effective. Compared to targeted testing, routine testing helped to discover more patients in earlier stages and those with heterosexually transmitted HIV infection.

Care Cascade for targeted tuberculosis testing and linkage to Care in Homeless Populations in the United States: a meta-analysis

BACKGROUND

Homelessness increases the risk of tuberculosis (TB) disease and latent TB infection (LTBI), but persons experiencing homelessness often lack access to testing and treatment. We assessed the yield of TB testing and linkage to care for programs targeting homeless populations in the United States.

METHODS

We conducted a comprehensive search of peer-reviewed and grey literature, adapting Cochrane systematic review methods. Two reviewers independently assessed study eligibility and abstracted key data on the testing to care cascade: number of persons reached, recruited for testing, tested for LTBI, with valid test results, referred to follow-up care, and initiating care. We used random effects to calculate pooled proportions and 95% confidence intervals (CI) of persons retained in each step via inverse-variance weighted meta-analysis, and cumulative proportions as products of adjacent step proportions.

RESULTS

We identified 23 studies published between 1986 and 2014, conducted in 12 states and 15 cities. Among studies using tuberculin skin tests (TST) we found that 93.7% (CI 72.4-100%) of persons reached were recruited, 97.9% (89.3-100%) of those recruited had tests placed, 85.5% (78.6-91.3%) of those with tests placed returned for reading, 99.9% (99.6-100%) of those with tests read had valid results, and 24.7% (21.0-28.5%) with valid results tested positive. All persons testing positive were referred to follow-up care, and 99.8% attended at least one session of follow-up care. Heterogeneity was high for most pooled proportions. For a hypothetical cohort of 1000 persons experiencing homelessness reached by a targeted testing program using TST, an estimated 917 were tested, 194 were positive, and all of these initiated follow-up care.

CONCLUSIONS

Targeted TB testing of persons experiencing homelessness appears effective in detecting LTBI and connecting persons to care and potential treatment. Future evaluations should assess diagnostic use of interferon gamma release assays and completion of treatment, and costs of testing and treatment.

Context and Applications of Targeted Genetic Testing, with Emphasis on Copy Number Variants

There has been a huge acceleration in our technical ability to detect variation in the human genome in recent years, and there has been a corresponding effort in clinical diagnostic laboratories to take advantage of this progress for the benefit of patients. There has, however, not been an equivalent increase in our understanding of human genetics and disease, not for lack of effort but due to the far greater complexity of understanding variation than the difficulties of detecting it. This chapter describes how software tools can be used to target clinical genetic diagnostic testing in order to exploit technical and scientific advances both efficiently and cost-effectively, while maximizing clinical utility.