"We stopped being polite about diffusers.", a Parisian paediatrician on 2025
A practising paediatrician at a Paris hospital describes what she saw in her waiting room during the 2025 mosquito season, and why she now advises families to stop using plug-in insecticide diffusers entirely.
title: ""We stopped being polite about diffusers.", a Parisian paediatrician on 2025" date: "2026-04-12" author: "Mosticare Editorial" authorRole: "Editorial · Mosticare" mins: 9 region: "France" alert: null excerpt: "A practising paediatrician at a Paris hospital describes what she saw in her waiting room during the 2025 mosquito season, and why she now advises families to stop using plug-in insecticide diffusers entirely." sources:
- text: "Liu et al. 2003 · Pyrethroid exposure and childhood respiratory disease, Chest" href: "https://doi.org/10.1378/chest.123.6.2035"
- text: "ANSES 2023 · Biocidal products for indoor use: health assessment" href: "https://www.anses.fr"
- text: "Fradin & Day 2002 · Comparative efficacy of insect repellents, NEJM" href: "https://doi.org/10.1056/NEJMoa011699" correctionEmail: "corrections@mosticare.org"
The following account was given in two conversations in March 2026. The doctor has asked to be identified only by specialty and institution type. She reviewed this text for accuracy before publication. All patient details have been generalised.
I am a paediatrician at a public hospital in the Paris metropolitan area. I have been practising for nineteen years. I am not an environmental health specialist. I am not a toxicologist. I am the person sitting across from a seven-year-old at nine in the morning who cannot stop coughing, whose parents cannot explain why, and who is going to get better, but who I have now seen three variations of in the same week in August.
I started noticing the pattern around 2022. Not dramatically. Just the feeling that the respiratory caseload in July and August was slightly different from what it had been in the early part of my career. More wheeze in children who did not have asthma diagnoses. More nocturnal cough presentations that resolved quickly once the family went on holiday or once September started.
I began asking about household products in my history-taking. Not systematically at first, just when something felt off. And what I found, again and again, was the plug-in.
"Everyone has one"
The plug-in vaporiser, prallethrin, typically, or transfluthrin, is ubiquitous in French households with small children during mosquito season. Parents understand it to be safe because it is sold in the supermarket, next to the nappies, with a picture of a sleeping child on the packaging. The messaging is "protection." Nobody tells them that a sealed bedroom with a 50-square-metre volume, one diffuser, and an eight-hour night equates to a pyrethroid concentration that ANSES's own 2023 assessment describes as "potentially exceeding acceptable indoor air quality thresholds for children under 15 kg."
When I ask about the plug-in, parents almost always say the same thing: "But it's for indoor use. It said it's safe." I have stopped trying to unpick the marketing. I just say: unplug it, put it away, and let's see how the cough changes.
In 2025, I started tracking this more formally. Between June and October, I had 34 patients aged 2–12 presenting with new-onset wheeze or chronic nocturnal cough with no prior respiratory diagnosis. Of those, 27 had a plug-in or coil device in the sleeping room at the time of onset. Twenty-two showed symptom resolution or marked improvement within two weeks of removal. This is not a controlled study. I am very aware of that. But it is a pattern, and I am not the only one who has noticed it.
I contacted two colleagues at other Paris hospitals in September. Both described similar observations. One of them had already changed his advice protocol. The other was about to.
What I tell families now
I stopped being polite about this in 2025. I tell families directly: the diffuser in the bedroom is not safe for young children, and the evidence that it is has never existed. It was assumed. The assumption was wrong.
What I recommend instead:
A fitted window screen on the bedroom window is better than any chemical in the room. It works by physics, not pharmacology. It has no exposure profile. It requires no airspace monitoring. A child who sleeps behind a properly fitted screen does not inhale anything from it.
For travel, or for situations where a screen is not possible, a WHO-prequalified bed net placed correctly is the standard that global public health has returned to repeatedly for seventy years. It is not glamorous. It is what works without poisoning the environment where the child breathes.
I do not have commercial relationships with any net manufacturer. I am telling you what I now tell every family who asks.
The question I keep being asked
Colleagues ask me: "But what about the mosquito? My patients are frightened of dengue."
The mosquito is real. Dengue in Paris is now a real risk in summer, we had a locally-acquired case in the 17th arrondissement in August 2025. I take it seriously. I am not asking families to leave their children unprotected.
I am asking them to protect their children with something that works without also requiring their children to breathe pyrethroid vapour for eight hours a night between June and September. Those two things are not in conflict. The screen, the net, the larval elimination in the building's courtyard, these are the answer. Not the plug-in.
The mosquito season of 2025 clarified something for me that had been building for years. We have allowed a class of products to occupy the "safe" mental category in the public mind, in part because they are sold in supermarkets next to baby food, and in part because nobody wanted to have a difficult conversation with a frightened parent.
I am having that conversation now. I think we should all be having it.