ALERT AND RESPONSE OPERATIONS

WHO perspective and guidance

on burden of dengue,

prevention and control and

integrated management

Dr Raman Velayudhan

Coordinator, WHO Geneva

Global Dengue Risk 2012.

Simmons CP et al. N Engl J Med 2012;366:1423-1432

Commitment Chronological list of World Health Assembly resolution and Regional Committee resolutions adopted since 2000:-

World Health Assembly

2002 - WHA 55:- Dengue fever and dengue haemorrhagic fever prevention and

Control. WHA 55.17

2014 – World Health Day April 7th – Vector borne diseases

2015 – EB and WHA 68 Dengue prevention and control

Regional Committee Resolutions (RCM):-

2001 – PAHO: Dengue and Dengue Haemorrhagic fever. CD43.R4

2008 – SEAR: Dengue prevention and control. SEA/RC61/R5

2008 – WPR: Dengue fever and dengue haemorrhagic fever prevention and

Control. WPR/RC59.R6

2011 – EMR: Dengue: call for urgent interventions for a rapidly expanding emerging

Diseases. EM/RC/58.R4

2013 – EURO Framework on Invasive species surveillance 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

The global strategy for dengue prevention and control (2012- 2020)

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

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

Deconstructing burden

• Different levels of severity

• Impact & cost are age-dependent

• Probability of lab-confirmed diagnosis low, especially for milder disease

Severe

Fever

Infection

{ Medically attended

(hopefully)

• Major Conclusions

• 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

Burden estimation

• 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

• 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

Case management: diagnostics

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

Case management: clinical management and classification

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

Integrated surveillance

• 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

• Effectiveness of any outbreak response has not been validated and

depends on timing of initiation.

Outbreak Response

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.

Sustainable vector management

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

• 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

Introduction of vaccines and combined interventions

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

l Challenges

– Need for synergistic effort

– Evidence for effectiveness of partnerships

Partnerships

STRATEGY IMPLEMENTATION NEEDS

Capacity building

Communication for

Behavioral outcomes

Advocacy and

Resource

mobilization

Partnership,

Coordination and

collaboration

Monitoring and

Evaluation

Technical

elements

Amarasinghe et alia, Emerging Infectious Diseases (2011) 17:1349-1354

Known or Suspected Dengue Endemic Countries: Africa

Known endemic

Suspected endemic

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)

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

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.

Community mobilisation

Malaria 1 Dengue OLD NEW

Population at risk 3.2 billion 2.5 billion 3.9

billion

Endemic countries 96 >100 128

Infections /year 214 million 50 million 70- 500

million

Severe Cases 3 million 2.1 million

?

Deaths/ year 438,000 20,000 10,000*

1) Global Malaria Report 2015 2) http://www.pdvi.org/about_dengue/GBD.asp and Brady et.al. PLoS Negl Trop Dis 2012; 6: e1760

• 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

A disease for the future ?

Guideline revision underway.

To be completed in 2016

Thank you VelayudhanR@who.int