HIV Diagnostics and Vaccines: It Takes Two to Tango.

Current serologic tests for HIV screening and confirmation of infection present challenges to the adoption of HIV vaccines. The detection of vaccine-induced HIV-1 antibodies in the absence of HIV-1 infection, referred to as vaccine-induced seropositivity/seroreactivity, confounds the interpretation of test results, causing misclassification of HIV-1 status with potential affiliated stigmatization. For HIV vaccines to be widely adopted with high community confidence and uptake, tests are needed that are agnostic to the vaccination status of tested individuals (ie, positive only for true HIV-1 infection). Successful development and deployment of such tests will require HIV vaccine developers to work in concert with diagnostic developers. Such tests will need to match today's high-performance standards (accuracy, cost-effectiveness, simplicity) for use in vaccinated and unvaccinated populations, especially in low- and middle-income countries with high HIV burden. Herein, we discuss the challenges and strategies for developing modified serologic HIV tests for concurrent deployment with HIV vaccines.

The relevance of target product profiles for manufacturers, experiences from the World Health Organization initiative for point-of-care testing for sexually transmitted infections.

BACKGROUND: Sexually transmitted infections (STIs) are a significant global public health issue that cause a high burden of disease, especially in low- and middle-income countries. Screening of key populations and early and accurate diagnosis of infection are critical. Testing for syphilis, Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, curable STIs, as well as the human papillomavirus (HPV), is frequently unavailable in low-resource settings. Tests for these STIs that can be used at the point of patient care (POCTs) are needed. In recent years, there has been increased attention for STI POCTs, but technical guidance, financial resources and advocacy for additional platforms/tests are required in order to foster the development of STI POCTs. The WHO Department of Sexual and Reproductive Health and Research (SRH) has developed target product profiles (TPPs), a form of technical guidance, for these STI diagnostics. METHODS: SRH conducted a survey of selected companies that are developing POCTs for one or more of the STIs mentioned above to better understand how these TPPs influence the diagnostic development process - to assess their impact. RESULTS: Survey respondents indicated that the STI POCT TPPs provided good guidance with respect to performance expectations and operational characteristics for the tests/platforms. In particular, optimal metrics for sensitivity, specificity, sample types, and time to result were considered to be very useful. Respondents also suggested ways to improve the relevance of the STI POCT TPPs. For example, since it is often not possible for developers to achieve every desired standard, it would be useful to prioritize each performance/operational characteristic of the test and to provide a rationale as to why certain characteristics are considered important. Respondents also emphasized the need to encourage industry participation in the TPP development process and to find creative ways, including via targeted emails, a WHO webpage directed at industry, or a coordinated communications plan to increase awareness of the TPPs. CONCLUSIONS: Companies value the STI POCT TPPs and want them to continue. In order to maximize impact, WHO should consider the proposals from the manufacturers in the interest of increasing and accelerating access to STI diagnostics and treatment in low-resource settings.

Call to action for health systems integration of point-of-care testing to mitigate the transmission and burden of sexually transmitted infections.

OBJECTIVES: In 2016, WHO estimated 376 million new cases of the four main curable STIs: gonorrhoea, chlamydia, trichomoniasis and syphilis. Further, an estimated 290 million women are infected with human papillomavirus. STIs may lead to severe reproductive health sequelae. Low-income and middle-income countries carry the highest global burden of STIs. A large proportion of urogenital and the vast majority of extragenital non-viral STI cases are asymptomatic. Screening key populations and early and accurate diagnosis are important to provide correct treatment and to control the spread of STIs. This article paints a picture of the state of technology of STI point-of-care testing (POCT) and its implications for health system integration. METHODS: The material for the STI POCT landscape was gathered from publicly available information, published and unpublished reports and prospectuses, and interviews with developers and manufacturers. RESULTS: The development of STI POCT is moving rapidly, and there are much more tests in the pipeline than in 2014, when the first STI POCT landscape analysis was published on the website of WHO. Several of the available tests need to be evaluated independently both in the laboratory and, of particular importance, in different points of care. CONCLUSION: This article reiterates the importance of accurate, rapid and affordable POCT to reach universal health coverage. While highlighting the rapid technical advances in this area, we argue that insufficient attention is being paid to health systems capacity and conditions to ensure the swift and rapid integration of current and future STI POCT. Unless the complexity of health systems, including context, institutions, adoption systems and problem perception, are recognised and mapped, simplistic approaches to policy design and programme implementation will result in poor realisation of intended outcomes and impact.

Epidemic preparedness: why is there a need to accelerate the development of diagnostics?

Global epidemics of infectious diseases are increasing in frequency and severity. Diagnostics are needed for rapid identification of the cause of the epidemic to facilitate effective control and prevention. Lessons learned from the recent Ebola virus and Zika virus epidemics are that delay in developing the right diagnostic for the right population at the right time has been a costly barrier to disease control and prevention. We believe that it is possible to accelerate and optimise diagnostic development through a five-pronged strategy: by doing a global landscape analysis of diagnostic availability worldwide; through strategic partnerships for accelerating test development, in particular with vaccine companies to identify novel diagnostic targets; by creating and sharing repositories of data, reagents, and well characterised specimens for advancing the development process; by involving key public and private stakeholders, including appropriate regulatory bodies and policy makers, to ensure rapid access for researchers to diagnostics; and last, by fostering an enabling environment for research and access to diagnostics in the countries that need them. The need is great, but not insurmountable and innovative and faster development pathways are urgently required to address current shortfalls.

Innovative and New Approaches to Laboratory Diagnosis of Zika and Dengue: A Meeting Report.

Epidemics of dengue, Zika, and other arboviral diseases are increasing in frequency and severity. Current efforts to rapidly identify and manage these epidemics are limited by the short diagnostic window in acute infection, the extensive serologic cross-reactivity among flaviviruses, and the lack of point-of-care diagnostic tools to detect these viral species in primary care settings. The Partnership for Dengue Control organized a workshop to review the current landscape of Flavivirus diagnostic tools, identified current gaps, and developed strategies to accelerate the adoption of promising novel technologies into national programs. The rate-limiting step to bringing new diagnostic tools to the market is access to reference materials and well-characterized clinical samples to facilitate performance evaluation. We suggest the creation of an international laboratory-response consortium for flaviviruses with a decentralized biobank of well-characterized samples to facilitate assay validation. Access to proficiency panels are needed to ensure quality control, in additional to in-country capacity building.

Advancing prevention of sexually transmitted infections through point-of-care testing: target product profiles and landscape analysis.

OBJECTIVES: Advancing the field of point-of-care testing (POCT) for STIs can rapidly and substantially improve STI control and prevention by providing targeted, essential STI services (case detection and screening). POCT enables definitive diagnosis and appropriate treatment in a single visit and home and community-based testing. METHODS: Since 2014, the WHO Department of Reproductive Health and Research, in collaboration with technical partners, has completed four landscape analyses of promising diagnostics for use at or near the point of patient care to detect syphilis, Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis and the human papillomavirus. The analyses comprised a literature review and interviews. Two International Technical Consultations on STI POCTs (2014 and 2015) resulted in the development of target product profiles (TPP). Experts in STI microbiology, laboratory diagnostics, clinical management, public health and epidemiology participated in the consultations with representation from all WHO regions. RESULTS: The landscape analysis identified diagnostic tests that are either available on the market, to be released in the near future or in the pipeline. The TPPs specify 28 analytical and operational characteristics of POCTs for use in different populations for surveillance, screening and case management. None of the tests that were identified in the landscape analysis met all of the targets of the TPPs. CONCLUSION: More efforts of the global health community are needed to accelerate access to affordable quality-assured STI POCTs, particularly in low- and middle-income countries, by supporting the development of new diagnostic platforms as well as strengthening the validation and implementation of existing diagnostics according to internationally endorsed standards and the best available evidence.

Sustainable HIV treatment in Africa through viral-load-informed differentiated care.

There are inefficiencies in current approaches to monitoring patients on antiretroviral therapy in sub-Saharan Africa. Patients typically attend clinics every 1 to 3 months for clinical assessment. The clinic costs are comparable with the costs of the drugs themselves and CD4 counts are measured every 6 months, but patients are rarely switched to second-line therapies. To ensure sustainability of treatment programmes, a transition to more cost-effective delivery of antiretroviral therapy is needed. In contrast to the CD4 count, measurement of the level of HIV RNA in plasma (the viral load) provides a direct measure of the current treatment effect. Viral-load-informed differentiated care is a means of tailoring care so that those with suppressed viral load visit the clinic less frequently and attention is focussed on those with unsuppressed viral load to promote adherence and timely switching to a second-line regimen. The most feasible approach to measuring viral load in many countries is to collect dried blood spot samples for testing in regional laboratories; however, there have been concerns over the sensitivity and specificity of this approach to define treatment failure and the delay in returning results to the clinic. We use modelling to synthesize evidence and evaluate the cost-effectiveness of viral-load-informed differentiated care, accounting for limitations of dried blood sample testing. We find that viral-load-informed differentiated care using dried blood sample testing is cost-effective and is a recommended strategy for patient monitoring, although further empirical evidence as the approach is rolled out would be of value. We also explore the potential benefits of point-of-care viral load tests that may become available in the future.

Using electronic readers to monitor progress toward elimination of mother-to-child transmission of HIV and syphilis: An opinion piece.

Electronic readers and smartphones have the potential to standardize the interpretation of rapid diagnostic tests (RDTs) and provide timely surveillance program data. RDTs are widely used for HIV and are being increasingly used for syphilis screening in pregnant women. Following the WHO initiative for the validation of elimination of mother-to-child transmission of HIV and syphilis, there is a need for more extensive testing and data monitoring. However, access to timely and accurate data can be challenging once testing is decentralized as data quality at remote sites is often difficult to verify. Electronic RDT readers can help to ensure quality and allow automated data transmission, creating an opportunity for real-time surveillance to inform control strategies and assess intervention impact. Furthermore, by linking the data to existing supply chain management software, stockouts can be minimized. The present opinion piece looks at the opportunities and challenges of using these tools within national elimination programs.

Impact of laboratory accreditation on patient care and the health system.

Accreditation is emerging as a preferred framework for building quality medical laboratory systems in resource-limited settings. Despite the low numbers of laboratories accredited to date, accreditation has the potential to improve the quality of health care for patients through the reduction of testing errors and attendant decreases in inappropriate treatment. Accredited laboratories can become more accountable and less dependent on external support. Efforts made to achieve accreditation may also lead to improvements in the management of laboratory networks by focusing attention on areas of greatest need and accelerating improvement in areas such as supply chain, training, and instrument maintenance. Laboratory accreditation may also have a positive influence on performance in other areas of health care systems by allowing laboratories to demonstrate high standards of service delivery. Accreditation may, thus, provide an effective mechanism for health system improvement yielding long-term benefits in the quality, cost-effectiveness, and sustainability of public health programs. Further studies are needed to strengthen the evidence on the benefits of accreditation and to justify the resources needed to implement accreditation programs aimed at improving the performance of laboratory systems.

The need for standardization in laboratory networks.

Expanding health care services for HIV, tuberculosis, and malaria has increased the demand for affordable and reliable laboratory diagnostics in resource-limited countries. Many countries are responding by upgrading their public laboratories and introducing new technology to provide expanded testing services into more regions. This expansion carries the risk of increasing the diversity of an already highly diverse technology and testing platform landscape, making it more difficult to manage laboratory networks across different levels of the health care system. To prevent this trend, countries are recommended to implement policies and guidelines that standardize test menus, technology, platforms, and commodities across multiple laboratories. The benefits of standardization include rational prioritization of resources for capacity development and more efficient supply chain management through volume-based price discounts for reagents and instrument service. Procurement procedures, including specification, prequalification, and contract negotiation, need to align with the standardization policies for maximum benefit. Standardization should be adhered to irrespective of whether procurement is centralized or decentralized or whether carried out by national bodies or development partners.

Challenges in implementing CD4 testing in resource-limited settings.

The scale-up of HIV antiretroviral therapy in recent years has led to a rapid increase in CD4 and CD4% count capacity to meet the diagnostic needs of staging and monitoring disease progression and treatment efficacy in adults and infants. The speed of implementation of this technology has been unrivalled in recent years and has met challenges with technology selection, laboratory infrastructure development, human resource limitations, cost-effectiveness, instrument maintenance, and ensuring testing access and quality. The lessons learned from dealing with these challenges have helped strengthen existing laboratory systems for other diagnostics. They may also facilitate the implementation of new diagnostics in future.