An upgraded bednet prevented 13 million malaria cases and saved 24,600 lives

The most effective malaria prevention tool of the last few years is not a vaccine, a gene drive or an app. It is a bednet, the same humble object that has hung over beds for a century, with one important difference. It carries a second insecticide. That single change is credited with preventing roughly 13 million malaria cases and saving 24,600 lives between 2019 and 2022.

The net is called Interceptor G2, and its story is a quiet correction to the assumption that progress always means complexity. For two decades the insecticide-treated net was the standard tool of malaria control, and it worked extraordinarily well, until mosquito resistance reduced its effect.

The problem the old net could not solve

Conventional bednets are treated with pyrethroids, a class of insecticide that for years caused mosquito mortality reliably and cheaply. The difficulty is the oldest one in biology. Use a single insecticide widely enough, for long enough, and the rare individuals that survive it become more common. Across much of sub-Saharan Africa, pyrethroid resistance spread through Anopheles mosquito populations. In many places the standard net became little more than a physical curtain. It stayed useful, but it no longer did the chemical work it was designed for.

This is the resistance trap, and it has no shortcut. Spraying alone does not solve it. The durable answer is a second mechanism that the mosquito's resistance has not yet developed against.

What changed

Interceptor G2 combines the familiar pyrethroid with a second active ingredient: chlorfenapyr. The two work in entirely different ways. The pyrethroid affects the nervous system. Chlorfenapyr disrupts the mosquito's ability to produce the energy its cells need, and it is toxic even to insects that resist the pyrethroid. A mosquito resistant to one is not automatically resistant to the other. Two independent mechanisms are harder for the mosquito to resist than one.

The chemistry was the easy part. The chemical company BASF spent the better part of a decade in the laboratory. Chlorfenapyr already existed, so the work was the unglamorous engineering problem of making it work on a net. The compound had to bind to fabric and stay there for three years of rubbing and washing. It also had to be safe enough to lie inches from a sleeping infant's face all night. That is a far harder brief than causing mosquito mortality in a Petri dish, and it is where the real engineering work lay.

The evidence

The proof came from field trials, not press releases. Medical entomologist Corine Ngufor, an associate professor at the London School of Hygiene & Tropical Medicine, led randomised evaluations in Benin, in Cotonou and Covè. The results were clear. In settings like these and in Mozambique, the new net cut malaria rates by roughly half. As the Gates Foundation summarised it, the dual-ingredient net proved "twice as effective at protecting children from getting malaria than the old nets."

Those are the words that matter most, because malaria is overwhelmingly a disease of children. Halving the rate is not a marginal gain. It is the difference between a manageable caseload and an overwhelmed clinic.

Turning a trial result into 13 million prevented cases required a second kind of work. It was less celebrated: getting the nets out at a price countries could afford. The first 35 million Interceptor G2 nets were delivered in 2019. The rollout was coordinated through the Innovative Vector Control Consortium, with financing arrangements that included the access-finance organisation MedAccess. Those arrangements were designed to drive the cost down and the volume up.

Tom McLean of the IVCC and his colleagues treated affordability as part of the product, not an afterthought. A net that works in a trial but is too expensive to deploy saves nobody.

Why this is the right kind of lesson

It is tempting, in a field crowded with gene drives and engineered mosquitoes, to treat a better bednet as a footnote. That would be a mistake. The Interceptor G2 story carries a principle worth holding onto: the strongest intervention is often the proven one, improved, not the newest one, unproven.

A net affects the mosquito that lands on it and little else. It needs no cold chain, no clinic, no electricity and no second dose. It works while you sleep, costs a few pounds, and lasts years. Combine it with the other measures that have worked at scale: source reduction, sterile-insect releases, and surveillance all play a part. Together they give protection that does not depend on any single technology.

For Europe, where the conversation is about the tiger mosquito moving north rather than malaria, the transferable lesson is the same. The barrier between you and the bite is still the most reliable protection there is. A treated net over the bed remains the standard the World Health Organization recommends for exactly this reason. The technology that halved malaria in Mozambique and the net over a bed in Lyon are closer cousins than they look.

What to watch next

Resistance does not stop; it adapts. The mosquitoes that survive pyrethroids will, in time, meet chlorfenapyr widely enough to begin the same slow selection again. That is why the people behind these nets are already working on third and fourth active ingredients to stay ahead of the insect. The pressure is permanent. The encouraging news from 2019 to 2022 is that the humble bednet still performs well. The unfashionable work of making an old tool better may be the most valuable improvement available.

What we know

Sources cited

1. Gates Foundation, A new mosquito net is saving lives from malaria (2026). https://www.gatesfoundation.org/ideas/articles/new-mosquito-net-saving-lives-malaria