The under-6-months rule: why every European parent's first mosquito decision is a physical net, not a repellent

Across France, Germany, Austria, Switzerland and Italy, the Asian tiger mosquito (Aedes albopictus) has moved from a curiosity of the Mediterranean coast to a fixture in suburban gardens, on terraces, and inside the houses that open onto them. ECDC distribution maps track it spreading north year on year, and the biting season in southern Europe now stretches across much of the year. For parents of newborns and young infants, the question is no longer whether mosquitoes will reach the baby's room. They will. The question is what to do about it.

The answer for a very young infant is simpler and stricter than much of the popular literature suggests. Paediatric and public-health bodies across Europe and North America converge on one point: do not apply repellent to the skin of a young baby, and use a physical barrier instead. The American Academy of Pediatrics (AAP) and the US Centers for Disease Control and Prevention (CDC) rule out repellents entirely before two months of age and recommend a mosquito net over the carrier, cot or pram. Through the early months of life, that physical barrier, an untreated net over the cot, pram or playpen, is the soundest default.

If you are short on time, read the five rules in the next section. For the regulatory detail on each repellent active ingredient, see the label section. For the practical setup, the physical-barrier section is the long version of what an infant-safe mosquito night actually looks like.

What every European parent needs to know in five rules

1. No skin-applied repellent on a very young infant. This includes DEET, picaridin (icaridin), IR3535, oil of lemon eucalyptus (also called PMD or p-menthane-3,8-diol), and citronella-based products. The AAP and CDC advise no repellent at all before two months of age, and a mosquito net instead. Oil of lemon eucalyptus carries a stricter floor still: it should not be used on children under three years.
2. The one alternative every body agrees on is a physical barrier. An untreated mosquito net over the cot is the standard option. Long-sleeved clothing, socks and full-length sleepsuits do the rest of the work.
3. Insecticide-treated nets exist, and they are not for an infant's cot. Treated nets are a global-health tool for malaria-endemic regions. They are regulated under the EU Biocidal Products Regulation (BPR), and WHO prequalification applies to them, not to plain untreated nets. They are not the measure for routine infant protection in non-endemic European homes. Treating a cot net with permethrin changes its regulatory class, its safety profile, and the population it is meant for.
4. A mosquito net for an infant must be untreated, breathable, and correctly fitted. The mesh size matters less than the tucking. The opening must be closed, and re-closed, every single time.
5. Mosquito control around the home is part of infant protection. Standing water in trays, gutters, plant saucers and toys is a breeding site within a short distance of the bedroom window. The net is half the picture. Reducing the breeding sites around the house is the other half.

Why avoiding skin repellent is the regulatory floor, not a preference

There is a tendency, particularly in copy aimed at new parents, to treat the avoidance of skin-applied repellents for the youngest infants as a lifestyle choice, "chemical-free", "natural", "pure". It is not a preference. It is the consistent position of the paediatric and regulatory bodies that have published on the topic.

The AAP and the CDC are the most commonly cited sources. Their position, set out in the AAP's HealthyChildren guidance and in the CDC Yellow Book travel chapter, is that DEET, picaridin and IR3535 should not be used on infants younger than two months; oil of lemon eucalyptus is excluded for children under three years; and the protective measure for a baby too young for repellent is a mosquito net over the carrier, cot or pram.

The European picture is structurally the same, though the agency names differ by country. France's Agence nationale de sécurité sanitaire (ANSES) publishes guidance on which repellents may be used to protect children, and advises mechanical protection (nets and clothing) for infants, with age limits on the active substances. Germany's Bundesinstitut für Risikobewertung (BfR) sets out the health considerations around repellent use. None of these bodies recommends a skin-applied repellent as the primary protection for a very young infant; all point to physical protection first.

The EU Biocidal Products Regulation (BPR, Regulation (EU) 528/2012) provides the regulatory frame around this advice. Repellent active ingredients, DEET, picaridin, IR3535 and PMD, are biocidal products under the BPR. An authorised product carries a label that specifies who it may be used on, the maximum concentration, and the age exclusions. A parent reading a repellent label will find, in the small print, the age below which the product must not be used.

It is the label that does the work. When it says "not suitable for children under X", that exclusion is a regulatory condition of use, not a marketing suggestion. Ignoring it puts the product outside its authorised use. The practical translation, for the parent of a very young infant, is that a skin repellent is not an option at all, at any concentration, in any formulation.

What each active ingredient actually says, on its own label

The repellent active ingredients most commonly sold to European consumers are not interchangeable on the age axis. Parents who treat "repellent" as a single category and swap freely between products can end up moving across different age restrictions without realising it.

DEET is the longest-established insect-repellent active ingredient. Under BPR review its consumer labelling excludes use on infants below a stated age (the AAP and CDC set that floor at two months) and caps the concentration, commonly at up to 30% in consumer products, and lower for children. The age exclusion is stated in the user-instructions block on the pack.

Picaridin (also called icaridin) is widely sold across Germany and Austria as the DEET alternative, typically at around 20% in consumer products. Its labelled minimum age varies by product and country, so the pack is the only reliable guide; the AAP treats it, like DEET, as suitable only from two months.

IR3535 is the third major synthetic repellent in European consumer use, sold at concentrations up to around 20% in lotions and sprays. As with the others, the labelled age floor varies by formulation and must be read on the pack.

Oil of lemon eucalyptus (also called PMD, p-menthane-3,8-diol, or Eucalyptus citriodora oil) is plant-derived, and its exclusion is stricter than the synthetics: it should not be used on children under three years. There is no oil-of-lemon-eucalyptus product authorised for a child under three. A parent who switches from DEET or picaridin to a "natural" lemon-eucalyptus product for a younger baby is moving to a more restrictive exclusion, not a less restrictive one.

The simplest reading is the correct one. No skin-applied repellent is authorised for the youngest infants, and none containing oil of lemon eucalyptus is authorised for a child under three. The alternatives are not "natural" products applied to skin; they are non-skin measures, physical barriers and source reduction.

The physical net alternative, in detail

The physical barrier for a young infant is not a single object. There are three structurally different forms, each with its own use case, and none is interchangeable with the others: a cot net, a pram net, and a room-wide net.

A cot or crib net drapes over the cot from a single suspension point, falling around the sleeping surface to below mattress height. The single-suspension form is the easiest for a parent to use correctly: there is no opening to remember to close, and the falling fabric self-tucks at the base. The mesh should be fine enough to keep mosquitoes and smaller biting insects out, and the fabric breathable, so that heat and humidity do not build up inside. For an infant, the net must be untreated: a plain physical barrier, with no insecticide.

Fit is what makes it work. The net must reach below mattress level all the way around, so that a mosquito landing on the outside cannot find a gap at mattress height and walk in. Two-piece designs (a frame plus a separate net) need the same care at the base.

A pram or stroller net does the same job outdoors: on the evening walk, the daytime nap in the garden, the trip to a cafe terrace. The same logic applies, full coverage with no gaps, including at the bottom edge against the pram frame. A net that drapes over the hood but does not reach inside the pram body is not doing the protective work.

A room-wide net is a different form again: a free-standing or ceiling-suspended net over a bed, or a fitted net on a playpen or travel cot. These are usually harder to fit correctly than a single-suspension cot net. A free-standing net for a small baby must be supported well above the infant's reach, because older infants grab and pull; a net an infant can reach at face height is not appropriate for this age group.

A common question is whether a long-sleeved bodysuit and sleepsuit replace the net. They do not. Clothing reduces the exposed skin available for bites but does not remove bites on the face, hands and feet. For a baby who is awake, the net is the answer; for a baby who is asleep, the net plus clothing is the answer. The two together are what make a summer-night routine work in a tiger-mosquito area.

The treated-net misconception

Mosquito nets split into two classes with very different regulatory profiles: untreated nets, and insecticide-treated nets. That boundary is a regulatory boundary, and the population each class is meant for is different.

Untreated nets are physical barriers. They are not biocidal products, and they carry no label under the EU BPR. They are the appropriate measure for routine infant protection in a non-endemic European home. WHO prequalification, BPR authorisation, and the chemistry of permethrin and other pyrethroids simply do not apply to them.

Insecticide-treated nets (ITNs) are a global-health intervention for malaria-endemic regions. They carry permethrin or another pyrethroid at controlled doses that repel and kill mosquitoes on contact, and the class is regulated under the WHO Prequalification of Vector Control Products and under the EU BPR. National malaria-control programmes deploy them in endemic regions (sub-Saharan Africa, parts of South-East Asia, parts of Latin America). They are not the measure for routine infant protection in non-endemic European homes. Treating a cot or pram with permethrin moves it out of the untreated class and into the treated-net class, with all the regulatory and labelling consequences that follow.

A treated net offered online for use around infants is a product built for a different setting, a different population, and a different regulatory frame. It is not the safer choice for a European baby. European consumer markets have generally not offered treated nets for infant use, for exactly this reason: insecticide-treated nets belong to the global-health toolkit, while protecting an infant in a European home is a job for an untreated physical barrier.

Source reduction, the half of infant protection people skip

The protection around the cot is half the picture. A net inside an open window, with a half-cleared gutter and water-filled plant saucers a few metres away, is doing the work indoors while the population that will test it is being recruited outdoors.

Aedes albopictus breeds in standing water at the household scale. The characteristic sites are blocked roof gutters; plant saucers; pet water bowls that are not refreshed daily; buckets, tarpaulins and toys that hold rainwater; discarded tyres; drains and inspection covers; and any container that holds water for more than a week in warm weather. The mosquito needs a small volume of water, a single saucer, not a pond. Its flight range is short, often little more than a hundred metres, so the breeding sites close to a house drive the population that enters it.

The work outside the net is structural: emptying the saucers, clearing the gutters, refreshing the pet bowl, covering the water butt, disposing of the old tyre. It is fitting screens on the windows and doors that open onto the garden. It is a fan on the terrace in the evening, because tiger mosquitoes are weak fliers and a steady cross-breeze cuts their feeding rate. Each of these is a household decision, and each reduces the number of mosquitoes that ever reach the cot net.

The combination, a fitted untreated net over the cot, source reduction around the house, screens on the windows, and a fan on the evening terrace, is what effective infant protection in a European tiger-mosquito area looks like in practice.

Common mistakes that parents make

A short list of the recurring missteps, in rough order of frequency.

Using a repellent on an infant too young for it, because the label was not read in full, or because a "natural" or "gentle" formulation was assumed to override the age limit. No skin-applied repellent is authorised for the youngest infants. The exclusion is in the regulation, not the marketing.

Using an insecticide-treated net for routine infant protection, because treated nets sound more effective. They are more effective against mosquitoes in a malaria-endemic setting; in a European infant-protection setting they are the wrong tool for the job.

Choosing a pram net that does not reach inside the pram body. A net draped over the hood but loose at the foot end lets mosquitoes in. It must reach inside the pram at the base and be tucked in.

Reaching for citronella candles, essential-oil diffusers, ultrasonic plug-in devices, or wearable repellent bands as the "natural" alternative. The European and US evidence base does not support reliable protection from these at the household scale. They are not a substitute for the net, and not a substitute for the source-reduction work.

Skipping the windows and screens. If the bedroom window is open without a screen, the net still works but the room is already full of mosquitoes. Screens on bedroom windows multiply the value of the net.

Treating "natural" or "chemical-free" as a safety guarantee. These are marketing words, not regulatory categories. A "natural" repellent still has an age floor (oil of lemon eucalyptus is excluded under three years), and a net's usefulness comes from its fit and mesh, not from a word on the label.

What the European picture looks like going into the 2026 season

The geography that drives the advice keeps moving north. ECDC maps show Aedes albopictus established across much of Italy, southern and central France, parts of south-western Germany, and parts of Austria and Switzerland, with further established populations around Madrid, in parts of Catalonia, in the Balkans, and in Greece. In France, Santé publique France reports the tiger mosquito colonising 81 of the 96 metropolitan departments as of 1 January 2025.

The 2025 season brought local transmission with it. Santé publique France recorded 809 locally acquired chikungunya cases and 30 locally acquired dengue cases in metropolitan France in 2025, the highest local chikungunya count the country has seen. Italy has recorded autochthonous dengue and chikungunya in recent seasons. The health, economic and social costs of that French season, documented in IJID Regions in 2026, are the reason households in Germany, Austria, Switzerland and northern Italy now think about the same mosquito that, a decade ago, was only a Mediterranean concern.

The takeaway for a parent is that this is no longer a Mediterranean-only decision. It applies wherever Aedes albopictus is now established, from Lyon and Milan to Vienna, Munich, Stuttgart and Bologna. Protecting a baby from mosquito bites is now part of an ordinary summer across much of western Europe.

The infant-safe routine, in short

If you have read this far, the routine is short. Use an untreated net over the cot, and check that it tucks below mattress level. Empty the plant saucers and standing water around the house. Fit a screen on the bedroom window. Refresh the pet bowl. And read the label before any repellent goes near a baby's skin. For a very young infant, the first mosquito decision is a physical barrier, not a repellent, and everything else follows from getting that one right.

Sources

• American Academy of Pediatrics (HealthyChildren): insect repellents and children, including advice for infants under two months and the use of mosquito netting. https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx
• CDC Yellow Book 2026: Mosquitoes, Ticks and Other Arthropods, protection guidance. https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html
• ECDC: invasive mosquito maps, current distribution of Aedes albopictus in Europe. https://www.ecdc.europa.eu/en/disease-vectors/surveillance-and-disease-data/invasive-mosquito-maps
• ECDC: Aedes albopictus factsheet (biology, breeding sites, seasonality). https://www.ecdc.europa.eu/en/disease-vectors/facts/mosquito-factsheets/aedes-albopictus
• Regulation (EU) 528/2012, the Biocidal Products Regulation (BPR): authorisation and labelling frame for repellent active substances (DEET, picaridin, IR3535, PMD) and for insecticide-treated nets. https://eur-lex.europa.eu/eli/reg/2012/528/oj
• WHO prequalification of vector-control products: assesses insecticidal products such as treated nets; untreated physical barriers, having no active substance, fall outside its scope. https://extranet.who.int/prequal/vector-control-products
• Santé publique France: chikungunya, dengue and Zika in metropolitan France, 2025 report (809 locally acquired chikungunya, 30 locally acquired dengue), published 6 May 2026. https://www.santepubliquefrance.fr/en/vector-borne-diseases/chikungunya/national-bulletin/chikungunya-dengue-and-zika-metropolitan-france-2025-report
• Santé publique France: enhanced surveillance data, mainland France 2025 (Aedes albopictus colonising 81 of 96 metropolitan departments as of 1 January 2025). https://www.santepubliquefrance.fr/maladies-a-transmission-vectorielle/chikungunya/chikungunya-dengue-zika-et-west-nile-donnees-de-la-surveillance-renforcee-en-france-hexagonale-2025
• Apouey B, Raimond V, Rouvière E, et al. From bites to ripple effects: the health, economic and social effects of arboviral epidemics in mainland France. IJID Regions 2026;20:100922. PMID 42382010. https://pubmed.ncbi.nlm.nih.gov/42382010/
• Bundesinstitut für Risikobewertung (BfR): repelling mosquitoes, ticks and flies, health-risk FAQ on repellents. https://www.bfr.bund.de/en/service/frequently-asked-questions/topic/repelling-mosquitoes-ticks-and-flies-are-there-any-health-risks-associated-with-using-repellents/
• ANSES guidance on mosquito repellents: which products to use to protect children (mechanical protection for infants, age limits on the active substances). https://www.anses.fr/fr/content/repulsifs-anti-moustiques-quels-produits-utiliser-pour-proteger-les-enfants
• EpiCentro (Istituto Superiore di Sanità): national arbovirus surveillance bulletins, Italy. https://www.epicentro.iss.it/arbovirosi/bollettini