This new WHObacked mosquito repellent cuts malaria risk by over 50%

Malaria and dengue continue to claim hundreds of thousands of lives each year, but scientists may have found a powerful new line of defence—WHO-endorsed spatial repellent sheets that emit mosquito-deterring vapours.

A new study titled Volatile pyrethroid spatial repellents for preventing mosquito bites: a systematic review and meta-analysis, published in eBioMedicine (The Lancet group), confirms that these repellents can cut mosquito bites by more than half. The study analysed 1.7 million mosquitoes over 25 years, marking the first significant innovation in mosquito control in four decades. What are spatial repellents and how do they work? Also known as spatial emanators, these lightweight paper-like devices release pyrethroid-based chemicals into the air that deter mosquitoes. Unlike topical lotions or coils, they don’t require direct skin application, heat, or electricity.

Roughly the size of a sheet of paper, they offer up to a year of protection against mosquitoes that carry malaria, dengue, Zika, yellow fever, and West Nile virus.

Repels more than 50 per cent of mosquito bites On average, the spatial repellents reduced mosquito bites by over 50 per cent. Some trials recorded up to 75 per cent effectiveness against Anopheles arabiensis, one of the most dangerous malaria-carrying species.

Importantly, they worked both indoors and outdoors—offering more versatility than bed nets or insecticide sprays, which are often location-limited.

Why these repellents matter in the fight against malaria Malaria still claims an estimated 608,000 lives each year, according to WHO data. Existing tools like insecticide-treated bed nets are only useful indoors and during the night. Repellent creams are expensive and require frequent reapplication, while coils offer only short bursts of protection.

Spatial repellents provide a more accessible, round-the-clock alternative—especially vital in remote regions with poor electricity supply.

Are these safe for home and public use? Yes, say researchers. The vapours released are similar to those used in WHO-approved bed nets, which have a well-documented safety profile. The study confirmed no new health risks associated with their long-term use.

“These are lightweight, affordable, and easy to use—ideal for both rural and urban settings,” the study authors said.

WHO’s nod likely to boost rollout in high-risk regions With WHO’s endorsement now confirmed, adoption of spatial repellents is expected to accelerate in high-burden regions across Africa, South America, and Southeast Asia, where vector-borne diseases remain a leading cause of death.

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