Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-8 (of 8 Records) |
Query Trace: Boeras D[original query] |
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The performance of using dried blood spot specimens for HIV-1 viral load testing: A systematic review and meta-analysis.
Vojnov L , Carmona S , Zeh C , Markby J , Boeras D , Prescott MR , Mayne ALH , Sawadogo S , Adje-Toure C , Zhang G , Perez Gonzalez M , Stevens WS , Doherty M , Yang C , Alexander H , Peter TF , Nkengasong J . PLoS Med 2022 19 (8) e1004076 BACKGROUND: Accurate routine HIV viral load testing is essential for assessing the efficacy of antiretroviral treatment (ART) regimens and the emergence of drug resistance. While the use of plasma specimens is the standard for viral load testing, its use is restricted by the limited ambient temperature stability of viral load biomarkers in whole blood and plasma during storage and transportation and the limited cold chain available between many health care facilities in resource-limited settings. Alternative specimen types and technologies, such as dried blood spots, may address these issues and increase access to viral load testing; however, their technical performance is unclear. To address this, we conducted a meta-analysis comparing viral load results from paired dried blood spot and plasma specimens analyzed with commonly used viral load testing technologies. METHODS AND FINDINGS: Standard databases, conferences, and gray literature were searched in 2013 and 2018. Nearly all studies identified (60) were conducted between 2007 and 2018. Data from 40 of the 60 studies were included in the meta-analysis, which accounted for a total of 10,871 paired dried blood spot:plasma data points. We used random effects models to determine the bias, accuracy, precision, and misclassification for each viral load technology and to account for between-study variation. Dried blood spot specimens produced consistently higher mean viral loads across all technologies when compared to plasma specimens. However, when used to identify virological failure, each technology compared best to plasma at a threshold of 1,000 copies/ml, the present World Health Organization recommended virological failure threshold. Some heterogeneity existed between technologies; however, 5 technologies had a sensitivity greater than 95%. Furthermore, 5 technologies had a specificity greater than 85% yet 2 technologies had a specificity less than 60% using a treatment failure threshold of 1,000 copies/ml. The study's main limitation was the direct applicability of findings as nearly all studies to date used dried blood spot samples prepared in laboratories using precision pipetting that resulted in consistent input volumes. CONCLUSIONS: This analysis provides evidence to support the implementation and scale-up of dried blood spot specimens for viral load testing using the same 1,000 copies/ml virological failure threshold as used with plasma specimens. This may support improved access to viral load testing in resource-limited settings lacking the required infrastructure and cold chain storage for testing with plasma specimens. |
Schistosomiasis is associated with incident HIV transmission and death in Zambia
Wall KM , Kilembe W , Vwalika B , Dinh C , Livingston P , Lee YM , Lakhi S , Boeras D , Naw HK , Brill I , Chomba E , Sharkey T , Parker R , Shutes E , Tichacek A , Secor WE , Allen S . PLoS Negl Trop Dis 2018 12 (12) e0006902 BACKGROUND: We examined relationships between schistosome infection, HIV transmission or acquisition, and all-cause death. METHODS: We retrospectively tested baseline sera from a heterosexual HIV-discordant couple cohort in Lusaka, Zambia with follow-up from 1994-2012 in a nested case-control design. Schistosome-specific antibody levels were measured by ELISA. Associations between baseline antibody response to schistosome antigens and incident HIV transmission, acquisition, and all-cause death stratified by gender and HIV status were assessed. In a subset of HIV- women and HIV+ men, we performed immunoblots to evaluate associations between Schistosoma haematobium or Schistosoma mansoni infection history and HIV incidence. RESULTS: Of 2,145 individuals, 59% had positive baseline schistosome-specific antibody responses. In HIV+ women and men, baseline schistosome-specific antibodies were associated with HIV transmission to partners (adjusted hazard ratio [aHR] = 1.8, p<0.005 and aHR = 1.4, p<0.05, respectively) and death in HIV+ women (aHR = 2.2, p<0.001). In 250 HIV- women, presence of S. haematobium-specific antibodies was associated with increased risk of HIV acquisition (aHR = 1.4, p<0.05). CONCLUSION: Schistosome infections were associated with increased transmission of HIV from both sexes, acquisition of HIV in women, and increased progression to death in HIV+ women. Establishing effective prevention and treatment strategies for schistosomiasis, including in urban adults, may reduce HIV incidence and death in HIV+ persons living in endemic areas. |
Re-imagining the future of diagnosis of neglected tropical diseases
Peeling RW , Boeras DI , Nkengasong J . Comput Struct Biotechnol J 2017 15 271-274 Neglected Tropical Diseases (NTDs) affect an estimated 1 billion people in 149 countries. The World Health Organization (WHO) prioritised 17 NTDs for control and elimination by 2020 and defined a Road Map to help countries reach these goals. Improved diagnostics for NTDs are essential for guiding treatment strategies at different thresholds of control, interruption of transmission, elimination and post-elimination surveillance. While substantial progress has been made in the last decade with chemotherapy, the same cannot be said of diagnostics, largely due to the perceived lack of a commercially viable market for NTD diagnostics. New sample in-answer out nucleic acid amplification technologies that can be performed at the point-of-care offer improved performance over current technologies and the potential to test for multiple pathogens using a single specimen. Finding commonalities for different NTDs in terms of geographic overlap, sentinel populations and treatment strategy will allow NTD programs to leverage these innovations to build cost-effective multiplex surveillance platforms. Connectivity solutions linking data from diagnostic laboratories and POC test readers/devices provide opportunities for automated surveillance systems to make health systems more efficient, improving patient outcomes and assessing impact of interventions in real time. New models of public-private product development partnerships are critical in leveraging diagnostic innovation in other priority area for better diagnosis, control and elimination of NTDs. |
Implementation science: the laboratory as a command centre
Boeras DI , Nkengasong JN , Peeling RW . Curr Opin HIV AIDS 2017 12 (2) 171-174 PURPOSE OF REVIEW: Recent advances in point-of-care technologies to ensure universal access to affordable quality-assured diagnostics have the potential to transform patient management, surveillance programmes, and control of infectious diseases. Decentralization of testing can put tremendous stresses on fragile health systems if the laboratory is not involved in the planning, introduction, and scale-up strategies. RECENT FINDINGS: The impact of investments in novel technologies can only be realized if these tests are evaluated, adopted, and scaled up within the healthcare system with appropriate planning and understanding of the local contexts in which these technologies will be used. SUMMARY: In this digital age, the laboratory needs to take on the role of the Command Centre for technology introduction and implementation. Implementation science is needed to understand the political, cultural, economic, and behavioural context for technology introduction. The new paradigm should include: building a comprehensive system of laboratories and point-of-care testing sites to provide quality-assured diagnostic services with good laboratory-clinic interface to build trust in test results and linkage to care; building and coordinating a comprehensive national surveillance and communication system for disease control and global health emergencies; conducting research to monitor the impact of new tools and interventions on improving patient care. |
Early antiretroviral therapy initiation: Access and equity of viral load testing for HIV treatment monitoring
Peter T , Ellenberger D , Kim AA , Boeras D , Messele T , Roberts T , Stevens W , Jani I , Abimiku A , Ford N , Katz Z , Nkengasong JN . Lancet Infect Dis 2016 17 (1) e26-e29 Scaling up access to HIV viral load testing for individuals undergoing antiretroviral therapy in low-resource settings is a global health priority, as emphasised by research showing the benefits of suppressed viral load for the individual and the whole population. Historically, large-scale diagnostic test implementation has been slow and incomplete because of service delivery and other challenges. Building on lessons from the past, in this Personal View we propose a new framework to accelerate viral load scale-up and ensure equitable access to this essential test. The framework includes the following steps: (1) ensuring adequate financial investment in scaling up this test; (2) achieving pricing agreements and consolidating procurement to lower prices of the test; (3) strengthening functional tiered laboratory networks and systems to expand access to reliable, high-quality testing across countries; (4) strengthening national leadership, with prioritisation of laboratory services; and (5) demand creation and uptake of test results by clinicians, nurses, and patients, which will be vital in ensuring viral load tests are appropriately used to improve the quality of care. The use of dried blood spots to stabilise and ship samples from clinics to laboratories, and the use of point-of-care diagnostic tests, will also be important for ensuring access, especially in settings with reduced laboratory capacity. For countries that have just started to scale up viral load testing, lessons can be learnt from countries such as Botswana, Brazil, South Africa, and Thailand, which have already established viral load programmes. This framework might be useful for guiding the implementation of viral load with the aim of achieving the new global HIV 90-90-90 goals by 2020. |
Access and quality of HIV-related point of care diagnostic testing in global health programs
Fonjungo PN , Boeras DI , Zeh C , Alexander H , Parekh BS , Nkengasong JN . Clin Infect Dis 2015 62 (3) 369-374 Access to point-of-care testing (POCT) improves patient care, especially in resource-limited settings where laboratory infrastructure is poor and the bulk of the population lives in rural settings. However, because of challenges in rolling out the technology and weak quality assurance measures, the promise of HIV-related POCT in resource-limited settings has not been fully exploited to improve patient care and impact public health. Because of these challenges, the Joint United Nations Programme on HIV/AIDS in partnership with other organizations recently launched the Diagnostics Access Initiative. Expanding HIV programs, including the "test and treat" strategies and the newly established UNAIDS 90-90-90 targets will require increased access to reliable and accurate POC test results. In this review, we examine various components that could improve access and uptake of quality-assured POC tests to ensure coverage and public health impact. These components include evaluation, policy, regulation, and innovative approaches to strengthen the quality of POCT. |
Monitoring the quality of HIV-1 viral load testing through proficiency testing program using dried tube specimens in resource-limited settings
Nguyen S , Ramos A , Chang J , Li B , Shanmugam V , Boeras D , Nkengasong JN , Yang C , Ellenberger D . J Clin Microbiol 2015 53 (4) 1129-36 BACKGROUND: HIV-1 RNA viral load (VL) levels are used for monitoring disease progression and antiretroviral therapy outcomes in HIV-infected patients. To assess the performance of laboratories conducting HIV-1 VL testing in resource-limited settings, the US Centers for Disease Control and Prevention implemented a voluntary, free-of-charge, external quality assurance program using dried tube specimens (DTSs). METHODS: DTS proficiency test (PT) panels consisting of 5 specimens were distributed between 2010 and 2012 at ambient temperature to participants. The results from participants (N ≥ 6) using the same assay were grouped, analyzed, and graded as acceptable within a group mean +/- 3SDs. Mean proficiency scores were calculated by dividing the combined PT scores with the number of testing cycles using a linear regression model. RESULTS: Between 2010 and 2012, the number of participants enrolled increased from 32 in 16 countries to 114 in 44 countries. 78.2% of participants reported results using 10 different VL assays. The rates of participants reporting acceptable results were 96.6% (Abbott), 96.3% (Roche COBAS), 94.5% (Roche Amplicor), 93.0% (Biocentric), and 89.3% (NucliSENS). The overall mean proficiency scores improved over time (p = 0.024). CONCLUSION: DTSs are a good alternative specimen type to plasma specimens for VL PT programs as they do not require cold chain transportation and can be used on polymerase chain reaction (PCR)-based assays. Our data suggest that the CDC HIV-1 VL PT program using DTSs positively impacts the testing performance of the participants which might translate into better and accurate VL testing services to patients. |
Role of donor genital tract HIV-1 diversity in the transmission bottleneck
Boeras DI , Hraber PT , Hurlston M , Evans-Strickfaden T , Bhattacharya T , Giorgi EE , Mulenga J , Karita E , Korber BT , Allen S , Hart CE , Derdeyn CA , Hunter E . Proc Natl Acad Sci U S A 2011 108 (46) E1156-63 The predominant mode of HIV-1 infection is heterosexual transmission, where a genetic bottleneck is imposed on the virus quasispecies. To probe whether limited genetic diversity in the genital tract (GT) of the transmitting partner drives this bottleneck, viral envelope sequences from the blood and genital fluids of eight transmission pairs from Rwanda and Zambia were analyzed. The chronically infected transmitting partner's virus population was heterogeneous with distinct genital subpopulations, and the virus populations within the GT of two of four women sampled longitudinally exhibited evidence of stability over time intervals on the order of weeks to months. Surprisingly, the transmitted founder variant was not derived from the predominant GT subpopulations. Rather, in each case, the transmitting variant was phylogenetically distinct from the sampled locally replicating population. Although the exact distribution of the virus population present in the GT at the time of transmission cannot be unambiguously defined in these human studies, it is unlikely, based on these data, that the transmission bottleneck is driven in every case by limited viral diversity in the donor GT or that HIV transmission is solely a stochastic event. |
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