WHO’s newly approved spatial emanators could help close the gaps in regions like Siaya County where malaria prevalence is above the national average.
The World Health Organization (WHO) has recommended a new mosquito control technology that could strengthen the global fight against malaria, particularly as growing insecticide resistance and changing mosquito behaviour threaten decades of progress.
WHO announced a conditional recommendation for spatial emanators or spatial repellents, a pioneering step in malaria vector control. WHO also prequalified the first two products in the new class of interventions that could be deployed by governments and development agencies in malaria-endemic countries.
The move is expected to give national malaria control programmes an additional tool to complement existing interventions like insecticide-treated nets (ITNs) and indoor residual spraying, which remain the cornerstone of malaria prevention.
Spatial emanators work by releasing active ingredients into the surrounding air, creating a protective space that repels, disorients or kills mosquitoes before they can bite people. Unlike bed nets, which primarily protect individuals while sleeping, the devices also offer protection during the day or in the evening when people are indoors but not under a net.
WHO said the technology could help address emerging challenges as mosquitoes increasingly adapt to existing control measures by biting earlier in the evening, outdoors, or avoiding insecticide-treated surfaces altogether.
Malaria control is affected by climate change, insecticide resistance, population growth, funding constraints
“This recommendation opens the door to a new intervention for national malaria control programmes at a time when innovation is urgently needed,” said Dr Daniel Ngamije, Acting Director for Malaria and Neglected Tropical Diseases at WHO.
“As rising insecticide resistance and changes in mosquito behaviour threaten the effectiveness of long-standing vector control tools, spatial emanators offer an innovative approach to help protect people at risk from infection,” he added.
The recommendation comes as malaria continues to place a heavy burden on many African countries, where the disease remains one of the leading causes of illness and death, particularly among children under five years and pregnant women. While insecticide-treated nets and indoor spraying have significantly reduced malaria transmission over the past two decades, health experts say progress has stalled in recent years because of climate change, insecticide resistance, population growth and funding constraints.
WHO stressed that spatial emanators are not intended to replace existing interventions but rather provide an additional layer of protection, especially in areas where traditional measures may be less effective.
Alongside the recommendation, WHO’s prequalification programme approved two products manufactured by SC Johnson & Son: Mosquito Shield and Guardian. Both use the active ingredient transfluthrin, which repels, disorients and kills malaria-transmitting mosquitoes. Mosquito Shield remains effective for up to one month, while Guardian can provide protection for up to 12 months, allowing countries to choose products that best suit their local distribution systems and replacement schedules.
Approved mosquito tools meet internationally recognised standards
The prequalification is expected to accelerate procurement by United Nations agencies, international donors and national governments by confirming that the products meet WHO standards for quality, safety and effectiveness. The WHO prequalification programme independently assesses health products before they are recommended for large-scale procurement, giving countries confidence that approved tools meet internationally recognised standards.
The announcement has also been welcomed by Unitaid, which supported research evaluating the effectiveness of spatial repellents. Dr Philippe Duneton, Executive Director of Unitaid, described the recommendation as an important milestone after years of scientific research.
“The WHO conditional recommendation for spatial repellents is a significant step forward in providing access to a new malaria vector control intervention,” he said. “Unitaid is proud to have supported research proving that spatial repellents, when used alongside insecticide-treated nets, can significantly reduce malaria transmission.”
He noted that innovation in malaria prevention has been limited for decades despite the disease continuing to kill hundreds of thousands of people every year. “At a time when progress against malaria has stalled, spatial repellents are the first new class of vector control intervention in decades, offering a new approach to protect people at risk,” Dr Duneton said, adding that Unitaid would continue supporting efforts to expand access to the technology while generating more evidence on its effectiveness when used independently.
Although WHO’s recommendation represents a significant scientific milestone, the agency acknowledged that important research questions remain. Current evidence primarily supports the use of spatial emanators alongside insecticide-treated nets. Scientists are still investigating how effective the devices are when used on their own, whether they can protect people outdoors, their usefulness during humanitarian emergencies, and their potential contribution to slowing insecticide resistance.
Spatial emanators also reduce infections caused by dengue virus, other arboviruses
Researchers are also exploring whether the same technology can help control other mosquito-borne diseases beyond malaria. Early findings from a clinical trial conducted in Peru showed that spatial emanators reduced infections caused by dengue virus and other arboviruses. A second major trial conducted in South-East Asia has recently been completed, with scientists currently analysing the results.
The latest recommendation reflects WHO’s broader strategy of combining multiple prevention tools rather than relying on a single intervention to combat malaria. For countries across Sub-Saharan Africa, where malaria continues to exact a significant health and economic toll, the addition of spatial emanators could provide another valuable weapon in protecting vulnerable communities, particularly as conventional mosquito control methods face growing biological and environmental challenges.
In 2023 alone, Kenya recorded about 3.3 million malaria cases, with transmission concentrated in lake and coastal counties such as Siaya, with a malaria prevalence rate of 26 per cent, far above the national average of about 6 per cent. Some health facilities have reported test positivity rates of between 30 and 70 per cent. Siaya is part of a Western Kenya belt, including Busia, Kakamega, Migori and Kisumu, that accounts for a large share of cases nationwide.
According to the World Malaria Report 2024, malaria struck an estimated 282 million people worldwide, about nine million more infections than the previous year. The disease claimed 610,000 lives, a rise from 598,000 deaths recorded in 2023.
Three out of every four malaria deaths were children under five
Nowhere is this burden heavier than in Africa. The WHO African Region carried 95 per cent of the world’s malaria cases and deaths in 2024, making the continent the epicentre of a disease that thrives on inequality, fragile health systems and poverty. Three out of every four malaria deaths were children under the age of five. The tragedy is concentrated in just a handful of nations, with Nigeria, the Democratic Republic of the Congo and Niger together accounting for more than half of all malaria deaths across Africa.
Despite the staggering toll, there is also a story of resilience and progress. Since 2000, the world has prevented an estimated 2.3 billion malaria infections and averted 14 million deaths. In 2024 alone, more than one million lives were saved, while 47 countries and one territory are now officially certified by WHO as free of the disease. Although malaria still claims hundreds of thousands of lives each year, hope is no longer measured only in promises, but in lives spared and nations liberated from its grip.
Health experts say continued investment in innovation, alongside sustained funding for proven interventions such as bed nets, prompt diagnosis and effective treatment, will remain essential if the world is to get back on track towards reducing malaria deaths and eventually eliminating the disease.
