Dengue Pre-vaccination screening strategies workshop

In the absence of truly effective and sustainable vector control measures, a dengue vaccine is urgently needed to protect the more than 3.6 billion people at risk for dengue virus infection.

New evidence has shown that the performance of the first licensed dengue vaccine, CYD-TDV, is dependent upon the serostatus (indicating past dengue infection) of recipients: an excess risk of severe dengue was revealed for seronegative vaccine recipients, while in seropositive vaccine recipients, the vaccine was efficacious and safe. Whether this serostatus-dependent vaccine performance will also be observed for the second-generation dengue vaccines is currently unknown. However, a differential performance based on baseline serostatus is theoretically possible for all live dengue vaccines.

SAGE provided revised recommendations in April 2018 on how best to use the CYD-TDV vaccine in populations at risk. It concluded that for countries considering vaccination as part of their dengue control program, a “pre-vaccination screening strategy” would be the preferred option, in which only dengue-seropositive persons are vaccinated. WHO and many expert panels have highlighted the urgent need for rapid diagnostic tests (RDT) that can determine serostatus to enable pre-vaccination screening.

To date, no RDT has been licensed for the indication of determining dengue serostatus. Pre-vaccination screening strategies will require RDTs that can be done at the point of care, provide rapid test results, are sensitive and specific, as well as inexpensive for use in a population-wide program. Policy makers will have to think through the risk-benefit of these diagnostic tests, determine the optimal age target for testing, and address complex issues around communication, implementation strategies, acceptability to stakeholders and communities, and cost-effectiveness.

Participants

This workshop, prepared by the PDC Pre-Vaccination Strategy Think Tank, is for EPI managers, front-line academic and public health scientists in vaccine introduction and mass vaccination, industry, diagnostics manufacturers, leaders of laboratory networks, regulatory authorities, and policy-makers with experience in vaccine introduction.

Workshop objectives

Address programmatic issues for pre-vaccination screening

• Share lessons learned from programs for individual screening prior to vaccination or clinical care (e.g. hepatitis B, hepatitis C)
• Lessons learned from vaccination programs targeted towards specific populations (e.g. HPV, Zoster, typhoid, cholera)

Assess rapid diagnostic tests (RDT) for past dengue infection screening

• Discuss the target product profile for RDTs to support a pre-vaccination screening strategy
• Present a landscape analysis on RDT characteristics, and their sensitivity and specificity in different settings where flaviviruses are endemic
• Map out the availability (and cost where available) of tests indicated for determining dengue serostatus
• Discuss a generic roadmap for accelerating the development and licensure of RDTs to determine serostatus

Discuss implementation strategies for pre-vaccination screening programs for dengue vaccines

• Address policy-makers’ perceptions and views on risk-benefit assessment of an RDT to determine serostatus as a pre-vaccination screening tool
• Address practical issues for Expanded Program on Immunization (EPI) program managers
• Discuss communication strategies, both for policy makers, the medical community and the lay public
• Elaborate on school-based campaigns versus other facility-based programs

Scientific Committee

• Cassandra Kelly, Foundation for Innovative New Diagnostics (FIND)
• May C. Chu, Department of Epidemiology, Colorado School of Public Health, University of Colorado, Anschutz Medical Center, Aurora
• Dagna Constenla, Department of International Health, Johns Hopkins Bloomberg School of Public Health
• Anna Durbin, The Anna Durbin Lab; Johns Hopkins University School of Medicine
• Duane J. Gubler, Emerging Infectious Diseases Program, Duke-NUS Medical School, Singapore
• Annelies Wilder-Smith, Partnership for Dengue Control; Lee Kong Chian School of Medicine, Singapore; Institute of Public Health, University of Heidelberg; Department of Global Health and Epidemiology, University of Umea
• In Kyu Yoon, International Vaccine Institute

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