In the global fight against mosquito-borne diseases, science has made a crucial breakthrough that promises a paradigm shift in protecting millions of people. After more than four decades without significant innovations in vector control, the World Health Organization (WHO) recently recommended a completely new class of products. This is a revolutionary technology, so-called spatial emanators, which offer long-lasting and effective protection against mosquitoes, the carriers of deadly diseases such as malaria, dengue fever, West Nile virus, yellow fever, and Zika. An extensive scientific analysis, which included data collected over more than 25 years, has confirmed the exceptional potential of this solution.

Researchers at the University of California, San Francisco (UCSF) conducted a systematic review of data on approximately 1.7 million mosquitoes, concluding that this form of repellent, which disperses active substances through the air, can prevent more than half of all mosquito bites. Specifically, an average protective efficacy of 56% was established, representing a significant reduction in the risk of infection. This news comes at a crucial moment, just after the World Health Organization (WHO) issued a historic recommendation this August, endorsing the use of spatial emanators as a new tool in the public health arsenal.

How does the new generation of protection work?

Spatial emanators represent a passive protection technology. They work on the principle of releasing volatile insecticides, such as metofluthrin or transfluthrin, into the surrounding air. These chemicals create an invisible protective "cloud" or "shield" in the space, which repels mosquitoes or disrupts their ability to find a host. Unlike previous methods, this technology does not require electricity, heating, or any external power source, making it ideal for use in remote and resource-poor areas, where mosquito-borne diseases are most prevalent.

The products are designed for maximum simplicity – they often come in the form of small strips, cards, or discs, no larger than a sheet of paper, which are simply hung in a room or outdoors. Their light weight, affordable price, and ease of use make them an extremely practical solution for protecting households in Africa, South America, and Southeast Asia, the regions most severely affected by malaria and other similar diseases. One of the key advantages is their continuous action – they provide protection day and night, thus filling the dangerous coverage gaps left by other methods, such as insecticide-treated nets, which are effective only at night and indoors.

The global impact of malaria and the limitations of existing methods

Malaria remains one of the deadliest diseases of our time. In 2023 alone, it claimed 597,000 lives, the vast majority of victims being children under the age of five in sub-Saharan Africa. The World Health Organization's goal is to reduce the malaria mortality rate by at least 90% by 2030 compared to 2015 and to eliminate the disease in at least 35 countries. However, progress towards achieving this goal has slowed in recent years. The reasons for this are multiple: the COVID-19 pandemic which diverted resources, insufficient funding for malaria control programs, and the growing problem of mosquito resistance to existing insecticides.

More than 40 species of mosquitoes from the genus Anopheles transmit the malaria parasite, and their feeding and resting habits vary greatly. This makes it difficult to apply a single solution for all situations. For example, insecticide-treated nets protect people only while they sleep, leaving them unprotected in the early evening and morning hours when many mosquitoes are active outdoors. In addition, topical repellents applied to the skin are often expensive, require regular reapplication, and are not always available to the most vulnerable populations. Insecticide coils, popular in many parts of the world, produce smoke that can be irritating and provide protection for only a few hours. Spatial emanators overcome these very shortcomings, offering consistent and long-lasting protection regardless of the time of day or location within the protected area.

Scientific confirmation of efficacy and a broad spectrum of action

A systematic review, the results of which were published in the scientific journal eBioMedicine, published by the prestigious The Lancet, brought together data from numerous studies conducted around the world. The analysis showed that spatial emanators provide protection not only against mosquitoes that transmit malaria but also against other dangerous species. This is of crucial importance because different species of mosquitoes have different behavioral patterns. Mosquitoes of the genus Anopheles, the vectors of malaria, mostly bite at night. On the other hand, mosquitoes of the genus Aedes, which transmit viruses such as dengue, Zika, and yellow fever, are active and bite predominantly during the day.

This ability to provide all-day protection makes spatial emanators a unique and versatile tool. The study confirmed their effectiveness against all key mosquito genera, albeit with varying degrees of success depending on the species and local conditions. Ingrid Chen, an associate professor of epidemiology and biostatistics at UCSF and the first author of the study, noted: "We finally have a new way to protect against mosquito bites, one that fills the gaps of existing methods. It is lightweight, affordable, and easy to use, so it can be deployed to save lives in all parts of the world."

Commercial products and the path to mass application

Several products using this technology are already on the market. Among them, BiteBarrier, Mosquito Shield, and Guardian stand out. BiteBarrier is the first such product to be sold in the United States and provides protection for up to 21 days. Mosquito Shield is effective for about 30 days, while the most advanced product, Guardian, offers protection that can last for up to a year, making it an extremely cost-effective and practical solution for long-term prevention.

The recommendation from the World Health Organization, issued on August 13, is a key step that opens the door for the mass application of these products, especially Mosquito Shield and Guardian. This recommendation allows major donors and international organizations, such as the Global Fund to Fight AIDS, Tuberculosis and Malaria, to subsidize and distribute these repellents in the countries most severely affected by malaria. This means that millions of people living in at-risk areas will soon have access to a new, effective, and simple method of protection. Nearly 50 researchers from 15 countries participated in this comprehensive analysis, which testifies to the global importance and collaboration needed to address this pressing public health problem.