Expanding the protection provided by vector control
Vector control continues to play a crucially important role in the prevention of vector-borne diseases such as malaria, dengue and chikungunya. The use of insecticide-treated mosquito nets and indoor residual spraying have done an incredible job in reducing the burden of malaria worldwide – still accounting for more than 70% of the malaria cases averted across Africa.
But these tools are designed to primarily protect people when they are indoors and (in the case of treated nets) when they are in bed. However, it is estimated that over 20% of infective malaria-mosquito bites in Sub-Saharan Africa occur at times when people are not in bed or are outdoors*.
Other interventions and tools are therefore needed to fill these gaps and continue to protect people in malaria-endemic areas during the course of their everyday lives.
That is the promise of spatial emanators, and why the recent news from the World Health Organisation (WHO) is such an important milestone. WHO has confirmed the public health value of spatial emanators for malaria vector control and prequalified the first two products (GuardianTM and ShieldTM from SC Johnson) in this intervention class. This marks a global recognition of a new class of tool in the fight against mosquito-borne diseases—one that has the potential to save additional lives and strengthen the long-term fight against malaria, dengue and other mosquito-borne diseases.
I congratulate SC Johnson and their current and historical partners for their perseverance in achieving this landmark step. The path through product development towards market availability of new vector control tools is complex. While it has arguably become clearer in more recent years, it still takes a significant investment of time and resources. This achievement is a testament to that commitment.
What is the significance of this for vector control?
Put simply, we have lacked tools that fill the transmission gaps described above. The fact that these emanator devices are also easy to deploy, are cost effective and don’t rely strongly on user compliance to be effective, are significant benefits.
It is probably fair to say that most people around the globe are already familiar with the concept of spatial emanators as a tool against mosquitoes (think of mosquito coils or plug-in emanators) – but the breakthrough has been in achieving longevity of effect in combination of passive emanation (i.e. without relying on an additional energy source). The long-lasting effect of GuardianTM makes for a very real prospect of public health impact.
IVCC’s perspective on spatial emanators
At IVCC, we often talk about our role in working with partners to build a sustainable toolbox of solutions. We need to sustain the impact of current core vector control tools, such as mosquito nets and indoor residual spraying, through additional modes of action that maintain their effectiveness in the face of insecticide resistance. At the same time, we need genuinely new approaches as part of the toolbox. Spatial emanators are the first new addition for malaria prevention in more than 20 years.
Spatial emanators are also key pillar in our own strategy. Not only do they provide, already demonstrated, public health value for indoor use, but they have the potential to provide protection to people outside in certain settings as well.
We have identified a number of opportunities to further explore the potential for spatial emanators. Doing so could boost their impact and strengthen their role in preventing vector-borne diseases:
- Indoor use: embedding and clarifying the use of the newly prequalified products alongside or, in some cases, perhaps instead of existing interventions.
- Outdoor use: further exploration is needed to understand the cost-effectiveness of such tools in providing personal protection in various outside use-cases.
- Identification and development of additional modes of action: understanding the relevance and threat of pyrethroid resistance to current tools and developing clarity on options to extend the range of modes of action available.
- Other disease applications beyond malaria: understanding the role of such tools alongside other approaches for dengue vectors for example.
As we move ahead with implementation of the IVCC strategy, matched to the needs of the vector control community, we expect to be able to help expand the application of spatial emanators, strengthen their utility, and make sure they deliver impact for the communities who need them most. We continue to partner with a number of organisations in this area to support these goals.
IVCC experience with spatial emanators in the Indo-Pacific
With funding from the Australian Government, our Indo-Pacific Initiative focuses on expanding the toolbox of vector control solutions for the region. In the first phase of the project, work was conducted with spatial emanators in some of the additional types of use pattern described above – this work confirmed the potential for such tools in outdoor settings. Through the NATNAT project in Papua New Guinea (PNG), we’ve helped establish the first national infrastructure for testing new tools at the PNG Institute of Medical Research. Among other activities, it is evaluating spatial emanators in local settings, generating the kind of evidence that supports the local decision makers to define their future vector control strategies.
Looking ahead
The WHO recommendation is a landmark moment, but it is not the end of the journey. To secure the future of spatial emanators, and of vector control more broadly, three things remain critical:
- Continued investment to keep both implementation programs and innovation moving forward.
- Policy leadership to translate evidence into adoption.
- Global collaboration to ensure tools reach the people who need them most.
Spatial emanators are not a silver bullet, but they are a vital addition to an integrated approach to vector management. Their success will depend on the same partnership, persistence, and support that brought us to this milestone.
A hopeful step forward
At IVCC, we remain committed to driving innovation so that communities worldwide are better protected against malaria and vector-borne diseases. WHO’s recommendation is a step forward not just for spatial emanators, but for the principle that innovation can, and must, keep improving our ability to fight against vector-borne diseases.
