Mérieux Foundation co-organized event
Dengue pre-vaccination screening strategies workshop
January 20 - 22, 2020 - Les Pensières Center for Global Health, Veyrier-du-Lac (France)
Dengue is a major public health problem with more than 3.6 billion people at risk for dengue virus (DENV) infection and an estimated 390 million infections annually in over 120 tropical and sub-tropical countries. In the absence of truly effective and sustainable vector control measures, a dengue vaccine is urgently needed. The first dengue vaccine was licensed in 2015; the live attenuated recombinant tetravalent vaccine CYD-TDV (Dengvaxia). However, new evidence highlighted the serostatus-dependent vaccine performance of Dengvaxia; a retrospective analysis of clinical trial data, stratifying participants according to their dengue serostatus before the first vaccine dose, revealed an excess risk of severe dengue in 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 Dengvaxia in populations at risk1: Countries considering the introduction of CYD-TDV should only do so if the minimization of the risk in seronegative individuals can be assured. The pre-vaccination screening is the preferred strategy as with such a strategy predominantly persons with evidence of a prior dengue infection would be vaccinated (based on serological test, or documentation of laboratory confirmed dengue infection in the past).
To support a pre-vaccination screening strategy, WHO and many expert panels highlighted the urgent need for rapid diagnostic tests (RDTs) to determine serostatus. To date, no RDT has been licensed for the indication of prior dengue infection status. Pre-vaccination screening strategies will benefit from RDTs that can be done at point of care, provide rapid test results, are sensitive and specific, as well as inexpensive for use in a population wide program. In January 2019, various dengue experts, vaccinologists, country representatives, key opinion leaders and diagnostic manufacturers met to discuss the characteristics of screening tests, the target product profile, and implementation strategies. The meeting report has been published.2 New advances on RDT development are now available and should be reviewed in order to accelerate its access in countries considering the introduction of CYD-TDV.
The implementation of the pre-vaccination screening strategy might encounter some programmatic hurdles and challenges that should be addressed. Finally, in the last months, several dengue outbreaks have been reported worldwide (Brazil, Bangladesh, Philippines, China, etc), and hence it is timely to discuss a public health strategy outbreak response.
Objectives of the meeting
Updates on new clinical data for CYD-TDV
- Discuss updates on recent clinical study results
- Address the impact of such data in terms of WHO recommendation / guidelines and on field implementation
Screening for prior dengue infection: Rapid diagnostic tests (RDTs) development updates
- Discuss RDT Target Product Profile (TPP) development status: where are we and next steps
- Updates on RDT development for pre-vaccination screening
- Address qualified- RDTs access for countries
Discuss implementation strategies for pre-vaccination screening programs for dengue vaccines
- Discuss practical issues for programmatic roll-out and get regional experiences feed-back on CYD-TDV
- Address programmatic challenges encountered by countries and the needs required for a successful implementation
- Discuss communication strategies with regards to vaccine confidence, both for policy makers, the medical community and the lay public
- Discuss cost-effectiveness data and modeling implementation approaches
Discuss Public health strategy for outbreak response
World Dengue Day target and expectations
NITAG experts, EPI managers, policy-makers with experience in vaccine introduction, front-line academic and public health scientists with expertise in vaccine introduction and mass vaccination, industry, diagnostics manufacturers, leaders of laboratory networks, regulatory authorities; WHO; CDC.