By Milliam Murigi
Across Africa, new-generation bed nets are being rolled out to fight malaria and tackle growing insecticide resistance.
Unlike the standard insecticide- treated nets that contain insecticides from the pyrethroid class, these new-generation nets contain additional active ingredients combined with pyrethroids.
They are designed to kill mosquitoes that have become resistant to older chemicals.
However, a new study published in Nature Communications suggests that while these modern mosquito nets do reduce malaria, their real-world impact is far lower than expected once everyday use, wear and human behavior are taken into account.
“We found out that the new-generation insecticide-treated nets work well in laboratory and controlled trial settings. But their effectiveness steadily declines in real life, as nets tear, insecticides weaken, and people do not always sleep under them consistently,” says Sarah Moore of Ifakara, who co-led the study
The result is a significant gap between what the technology promises and what communities actually experience. According to Moore, while these nets provide greater entomological efficacy against resistant mosquitoes, their effectiveness against malaria transmission also depends on other factors, such as durability, access, usage, and activity patterns of hosts and vectors.
The new findings do not dispute the value of next-generation nets. Instead, they offer a caution: technology alone cannot defeat malaria. Without attention to how people live, sleep and protect themselves both indoors and outdoors even the best tools will fall short.
The study highlights the need for stronger net quality, consistent use, community education, and complementary strategies to protect people from mosquito bites outside sleeping hours.
“This study does not question the value of these nets but it shows that technology alone is not enough. Better net quality, regular use, community education, and ways to protect people from mosquito bites outside sleeping hours are all needed,” she added.
Scientists from the Swiss Tropical and Public Health Institute (Swiss TPH) and Tanzania’s Ifakara Health Institute examined two widely used next-generation nets—Interceptor® G2 and Olyset® Plus both designed to overcome resistance to traditional pyrethroid insecticides.
Rather than focusing on a single measure of success, the researchers analyzed net performance across multiple stages, from the moment a mosquito touches the net to the broader impact on malaria infection in communities. They describe this process as a “cascade of effectiveness,” showing how protection weakens step by step as real-life factors are introduced.
“In controlled trials, the nets performed well. They reduced mosquito biting, killed insecticide-resistant mosquitoes, and lowered malaria transmission better than older, pyrethroid-only nets,” said Moore.
However, when researchers factored in real-world conditions such as how often people actually sleep under nets, how quickly nets wear out, and when mosquitoes bite the overall impact dropped sharply. Over time, holes in nets, repeated washing, and reduced insecticide strength further weakened their protective effect.
To understand how these dynamics play out at scale, the researchers combined mosquito data from trials conducted in Tanzania, Benin and Côte d’Ivoire with malaria infection data from community studies in Tanzania, Uganda and Benin.
They then used a mathematical model to simulate how nets perform over time in real households. The model showed that human behavior—how long people stay in bed, how consistently nets are used, and how quickly nets deteriorate—can be just as important as the insecticides themselves.
“Our results show that protection is lost at multiple points,” the researchers note, emphasizing that no single intervention can compensate for weaknesses across the entire chain of use.
In conclusion, the study recommends that to maximize impact, countries may need to invest more in net durability, behavior-change campaigns that encourage consistent use, and additional measures such as indoor residual spraying or tools that protect people during evening and early-morning hours when nets offer little protection.
