Por Renan Filho · 2026-09-24The French health authorities have begun a controversial new tactic in the war against dengue fever: releasing infertile Asian tiger mosquitoes (Aedes albopictus) into the wild. The pilot project, conducted in the southern city of Montpellier and the overseas territory of Réunion, aims to suppress the mosquito population that carries the dengue virus. According to a statement from the French National Health Agency (Santé Publique France), the programme involves breeding millions of male mosquitoes in laboratories, sterilising them with a low dose of radiation, and then releasing them to mate with wild females, which produces no offspring. Over time, this is expected to collapse the local mosquito population and reduce dengue transmission.
The initiative comes as Europe faces an unprecedented rise in dengue cases, propelled by climate change and global trade. The European Centre for Disease Prevention and Control (ECDC) reported over 1,300 locally acquired cases in the EU in 2024 — a record. The Asian tiger mosquito, which now thrives across southern Europe, is the primary vector. France, Italy and Spain have been hardest hit. In response, the French government has allocated €10 million to this project, with plans to expand to other regions if successful.
But at what cost? The French taxpayer is footing a bill that critics argue could be better spent on cheaper, more effective measures. The FORTIS editorial line holds that governments, particularly those in Europe, have a track record of overspending on flashy projects while neglecting basic public health infrastructure. In this case, the sterile insect technique (SIT) is not new — it has been used for decades against agricultural pests like the screwworm fly — but its application to urban mosquitoes is expensive and logistically complex. The programme requires continuous releases every few weeks, as sterilised males only live for about a week. The cost per hectare is estimated at €500 per year, compared to just €100 for targeted larviciding and community clean-up campaigns.
Furthermore, there is the question of unintended consequences. Although the male mosquitoes do not bite, the release of millions of any species alters the local ecosystem. Predators such as birds, bats and dragonflies may suffer from a sudden loss of prey. And if the programme fails to maintain sterility — for example, if some females are accidentally released — the result could be a larger, fertile population. French officials have assured the public that rigorous quality control is in place, but history suggests otherwise. In Brazil, a similar SIT project against the Aedes aegypti mosquito was abandoned after two years due to high costs and limited impact, as noted by a 2023 study in the journal PLoS Neglected Tropical Diseases.
From a free-market perspective, the most efficient solution would be to incentivise private sector innovations, such as mosquito traps, repellents and gene-editing technologies, through deregulation and reduced red tape. Instead, the French state is betting on a centralised, bureaucratic approach that stifles competition. The French pharmaceutical industry, for example, could develop affordable vaccines or antiviral treatments if government subsidies were redirected from mosquito control to research and development. The dengue vaccine market is already growing, but it is hampered by complex regulatory hurdles in the EU.
A counterpoint must be made: the sterile insect technique is environmentally friendly compared to chemical insecticides, which can harm pollinators and accumulate in the food chain. The World Health Organization has endorsed SIT as a complementary tool. However, advocates for minimal state intervention would argue that local communities and private companies should decide the best pest control strategy, not a distant Parisian bureaucracy. The programme also raises sovereignty concerns: should France be meddling with natural ecosystems without a thorough risk assessment that is open to public scrutiny?
Ultimately, the French experiment is a high-cost gamble. If it works, it could pave the way for other European nations, including the United Kingdom, to adopt similar schemes. The UK's National Health Service has already expressed interest in the results, according to a briefing paper from the UK Health Security Agency. But British taxpayers should be wary: before replicating the model, a rigorous cost-benefit analysis must be conducted. The FORTIS analysis suggests that market-based solutions — like public-private partnerships for innovative repellents or fast-tracked vaccine trials — would deliver greater value for money. In the meantime, citizens in affected areas would do well to drain standing water and use personal repellents rather than rely on government-sponsored mosquito armies.