WHO-Endorsed Mosquito Repellent Cuts Malaria Risk by Over 50 Percent: Study Finds - Video

A recent international study published in eBioMedicine has found that WHO-endorsed spatial repellent sheets can reduce mosquito bites by over 50%, offering a powerful new tool in the fight against mosquito-borne diseases such as malaria and dengue. The study analyzed data on 1.7 million mosquitoes collected over 25 years to evaluate the effectiveness of these repellents.

These spatial repellents, also called spatial emanators, are lightweight, paper-like sheets that release pyrethroid-based vapours to deter mosquitoes without requiring direct skin application, heat, or electricity. Roughly the size of a sheet of paper, they protect up to a year against mosquitoes that carry diseases including malaria, dengue, Zika, yellow fever, and West Nile virus.

The study’s findings showed that spatial repellents reduced mosquito bites by more than half on average, with some trials achieving up to 75% effectiveness against Anopheles arabiensis, a dangerous malaria vector. Importantly, the repellents worked both indoors and outdoors, offering more versatile protection compared to bed nets or insecticide sprays, which are often limited by location or time.

Malaria claims an estimated 608,000 lives annually worldwide, and current tools like insecticide-treated bed nets offer protection mainly indoors at night. Repellent creams and coils provide only limited or costly solutions. The long-lasting and easy-to-use spatial repellents thus represent a major breakthrough, especially for remote areas with poor electricity supply.

The vapours released are similar to those used in WHO-approved bed nets, with no new health risks detected in long-term use. "These are lightweight, affordable, and ideal for rural and urban settings," the study authors said.

Reference: Chen, Ingrid Chena, Sarah L. Millera , Daniel Msellemuc , Aidi G. Lugengec , Johnson Kyeba Swaic , Nicole Acheed , Marta Andrésc,e,f , Christopher S. Bibbsg , Theeraphap Chareonviriyaphaph , J. Derek Charlwoodi , Greg Devine; Volatile pyrethroid spatial repellents for preventing mosquito bites: a systematic review and meta-analysis; eBioMedicine, Volume 0, Issue 0, 105891; DOI: 10.1016/j.ebiom.2025.105891