HIV Diagnostics and Vaccines: It Takes Two to Tango

Current serological 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 that are agnostic to vaccination status (i.e., only positive for true HIV-1 infection) of tested individuals are needed. 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 both 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 serological 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.

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.

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.

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.

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.

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.

Tensions in public health policy: patient engagement, evidence-based public health and health inequalities

This paper examines the proposition that there are considerable tensions between key strategies in health policy--namely, evidence-based approaches to population health improvement, reduction of health inequalities, and public and patient engagement--using (1) a critical analysis of the intersection of evidence-based public health, patient and public engagement, and health inequalities policies from a social constructionist perspective and (2) mathematical modelling of paternalistic and shared decision making in the management of hypertension in a random age and sex stratified community sample of residents of south east Northumberland, UK. It is concluded that there may be unintended effects on population health of incongruities in major components of public health policy. Greater public and patient engagement may militate against the disease prevention goals of evidence-based policy, and may better engage sections of the population who already benefit from greater access and better health associated with social status and opportunity, serving to increase inequalities by further marginalising those already suffering from relative exclusion.

Comparison of Vibrio cholerae O139 with V. cholerae O1 classical and El Tor biotypes

Vibrio cholerae O139 is a recently identified non-O1 V. cholerae strain responsible for outbreaks of epidemic cholera in India, Bangladesh, and Thailand in the past 2 years. Other workers have demonstrated the presence of the cholera toxin genetic element in V. cholerae O139, unlike the situation for other non-O1 V. cholerae strains. We sought to compare further this strain with strains of V. cholerae O1, classical and El Tor biotypes, by classic microbiologic methods, Southern blot analysis for restriction fragment length polymorphisms with probes for iron-regulated genes of V. cholerae O1, and comparisons of outer membrane protein profiles. Our results were similar for V. cholerae O139 and the El Tor biotype of V. cholerae O1, with the exception of the constitutive expression in V. cholerae O139 of OmpS, an outer membrane protein that was maltose inducible in comparison strains of V. cholerae O1.