WHO perspective and guidance on burden of dengue, prevention and control and integrated management

Transcription

1 WHO perspective and guidance on burden of dengue, prevention and control and integrated management Dr Raman Velayudhan Coordinator, WHO Geneva ALERT AND RESPONSE OPERATIONS

2 Global Dengue Risk Simmons CP et al. N Engl J Med 2012;366:

3 Commitment Chronological list of World Health Assembly resolution and Regional Committee resolutions adopted since 2000:- World Health Assembly WHA 55:- Dengue fever and dengue haemorrhagic fever prevention and Control. WHA World Health Day April 7 th Vector borne diseases 2015 EB and WHA 68 Dengue prevention and control Regional Committee Resolutions (RCM): PAHO: Dengue and Dengue Haemorrhagic fever. CD43.R SEAR: Dengue prevention and control. SEA/RC61/R WPR: Dengue fever and dengue haemorrhagic fever prevention and Control. WPR/RC59.R EMR: Dengue: call for urgent interventions for a rapidly expanding emerging Diseases. EM/RC/58.R EURO Framework on Invasive species surveillance and control

4 The global strategy for dengue prevention and control ( ) Goal: To reduce the burden of dengue Objectives: To reduce dengue mortality by at least 50% by 2020* To reduce dengue morbidity by at least 25% by 2020* To estimate the true burden of the disease by 2015 Technical element 1: Diagnosis and case management Technical element 2: Integrated surveillance and outbreak preparedness Technical element 3: Sustainable vector control Technical element 4: Future vaccine implementation Technical element 5: Basic operational and implementation research Enabling factors for effective implementation of the global strategy: Advocacy and resource mobilization; Partnership, coordination and collaboration; Communication to achieve behavioral outcomes; Capacity building; and Monitoring and evaluation

5 Burden Project objectives 1. To carry out needs assessment in select priority countries and develop and integrate all heath care providers dengue data in the national health information system; 2. Develop and field test a guidance document on estimation of true burden of dengue at national level including real time tracking of cases. 3. To estimate the economic burden of dengue during outbreaks /epidemics on health systems in selected countries

6 Selection and obtaining approval of participating countries in the project Brazil Mexico Sri Lanka Maldives Singapore (tbc) New Caledonia (tbc) Cambodia Tanzania (tbc) Fiji (tbc) Ecuador Criteria for the selection of countries:- endemicity of dengue; existence of a national programme; existence of health information system; availability of designated staff as dengue focal point; potential for introduction and evaluation of new tools

7 Deconstructing burden Different levels of severity Impact & cost are agedependent Medically attended (hopefully) Probability of labconfirmed diagnosis low, especially for milder disease { Severe Fever Infection

8 Major Conclusions Burden estimation WHO endorses and uses the burden estimates derived from the Oxford group studies. The estimates and risk map will be updated in 2015 using new data 91 cohorts available, 47 are using D/SD Regular surveillance data continue to be collected and used WHO is piloting burden estimation in 5 countries Challenges The gold standard for measuring dengue incidence is active detection through serology, but case detection from hospitalization is more commonly used Need to refine burden estimates for a better prediction framework using force of infection

9 Major Conclusions Availability of RDT/NS1 Progress has been made on evaluating the performance and utility of different kinds of diagnostic tests (IGM-based, NS1- based, Combination IgM/NS1, molecular diagnostics) Laboratory networks have been established in some regions Challenges Case management: diagnostics Performance of kits varies across populations and countries and manufacturers needs an evaluation process Resources for the use of diagnostics Strengthening global dengue laboratory networks globally requires enrolment and supporting development of national laboratories

10 Case management: clinical management and classification Major Conclusions Case classification (D/SD) and treatment algorithms have been developed aiming to reduce case mortality and help clinicians for triage. Implementation/acceptance varies across regions and countries Ongoing studies will provide more information on the predictive value of warning signs and case definitions Challenges Opinion varies about the redefining case classifications for dengue Harmonizing classifications is necessary based on solid evidence

11 Integrated surveillance l Major Conclusions Integrated surveillance is important for risk assessment and situation awareness Integrated surveillance can support outbreak preparedness and development of appropriate public messaging. l Challenges Prioritizing combinations of components that are applicable to resource-limited settings Surveillance must be followed with a locally appropriate response, however evidence supporting what works is severely limited

12 Major Conclusions Primary purpose of outbreak response is to meet peak demand during epidemics. Theoretically early outbreak detection and prediction provides an opportunity for interventions to moderate the size of the outbreak, especially if the response is early and robust. Ongoing studies are attempting to establish systems for outbreak detection and prediction using hospitalized cases as a parameter There are instances where outbreak control has been successful in curtailing dengue (eg Iquitos and Cairns) Challenges Identification of key parameters for each epidemiological setting for prediction of outbreaks Improving quality of data Outbreak Response Effectiveness of any outbreak response has not been validated and depends on timing of initiation.

13 Sustainable vector management l Major Conclusions Multiple tools are available Promising tools are in the pipeline (eg. Wolbachia, GM mosquitoes, vector traps, environmental management) Current and new tools and strategies have not been systematically evaluated for dengue prevention/ control against epidemiological outcomes and cost effectiveness l Challenges Scalability, coverage, sustainability, acceptability and quality of delivery remain an issue. Implementation of best practices in vector control studies in relation to dengue.

14 A Critical Assessment of Vector Control for Dengue Prevention NL Achee, F Gould, TA Perkins, RC Reiner, Jr., AC Morrison, S Richie, DJ Gubler, and TW Scott

15 Introduction of vaccines and combined interventions Major Conclusions Recent results on the first successful Phase III trials were published A number of candidates in clinical and preclinical pipeline Dengue is challenging to model, but several approaches are underway to model the impact of vector control and vaccine interventions Countries that wish to introduce the vaccine will need to embark on preparatory measures Challenges Potential public health impact and cost effectiveness of the first commercially available vaccine remains to be determined Challenges remain in the implementation (eg. target populations, vaccine schedules, acceptability, affordability, long term effectiveness) Application of modelling framework to combine vaccines and vector control

16 Partnerships l l Major Conclusions Partnership for Dengue Control (PDC) Integrated approach in dengue control as a concept Three major objectives: 1) developing the research agenda, 2) develop advocacy and communication and 3) ensuring sustainability through fundraising. Intersectoral partnerships Health sector, environment sector and community partnerships for dengue control are essential (eg. Singapore) Regional partnerships Several regional partnerships exist, for example- UNITEDengue Challenges Need for synergistic effort Evidence for effectiveness of partnerships

17 STRATEGY IMPLEMENTATION NEEDS Communication for Behavioral outcomes Capacity building Technical Advocacy and Resource mobilization Monitoring and Evaluation elements Partnership, Coordination and collaboration

18 Known or Suspected Dengue Endemic Countries: Africa Known endemic Suspected endemic Amarasinghe et alia, Emerging Infectious Diseases (2011) 17:

19 Urban, semi-urban and rural movement Human movement critical and understudied component in transmission Facilitate identification of hot spots, prompt response and suppress outbreaks Surveillance, intervention and prevention Points of entry needs to be monitored for vectors under IHR (2005)

20 Climate change favours the vectors Erratic access to piped water may aggravate dengue incidence if it leads to increased domestic water storage. Increase in temperature favours the multiplication of the vector and the virus Rainfall, relative humidity, El nino all plays a role in transmission and more studies are needed

21 Community mobilisation First CRCT of success of vector control. Each site implementing the intervention in its own way has the advantage of local customization and strong community engagement.

22 Malaria 1 OLD Dengue NEW Population at risk 3.2 billion 2.5 billion 3.9 billion Endemic countries 96 > Infections /year 214 million 50 million million Severe Cases 3 million 2.1 million? Deaths/ year 438,000 20,000 10,000* 1) Global Malaria Report ) and Brady et.al. PLoS Negl Trop Dis 2012; 6: e1760

23 A disease for the future? Uncertain distribution and burden As malaria declines, dengue rises Impact of Environmental changes Silent expansion of the vector Urban health services and systems needs to be addressed

24 Guideline revision underway. To be completed in 2016 Thank you