It starts like an ordinary cold, a runny nose and a little cough, but for some babies it turns into a harder struggle to breathe. Respiratory syncytial virus is very common, and most babies catch it by age 2. Knowing the signs of RSV in babies, and which ones mean you need help quickly, helps you act with confidence.
Quick answer: RSV in babies
- Very common: most children have RSV by their second birthday, mostly in autumn and winter.
- Usually mild: cold-like symptoms that improve in 1 to 2 weeks.
- Can be serious in babies under 6 months, premature babies and those with heart or lung conditions, often causing bronchiolitis.
- Prevention: antibody injections for babies and RSV vaccines in pregnancy are now available in many countries.
Symptoms of RSV
- runny or blocked nose and sneezing
- cough, often getting worse over a few days
- mild fever
- feeding less than usual
- irritability or sleepiness
Warning signs of breathing trouble
- fast breathing, or breathing that looks like hard work
- the skin between or below the ribs pulling in with each breath
- grunting, wheezing or flaring nostrils
- pauses in breathing, or blue or grey lips: call emergency services
- taking less than half their usual feeds, or fewer wet nappies
RSV is the most common cause of bronchiolitis. See bronchiolitis in infants.
Caring for your baby at home
- Offer smaller, more frequent feeds to keep your baby hydrated.
- Clear the nose with saline drops and gentle suction before feeds.
- Use paracetamol (acetaminophen) for fever or discomfort if needed, at the right dose.
- Keep your baby upright while awake, but always place them on their back to sleep.
- Keep the home smoke-free.
Antibiotics do not help RSV, as it is a virus. See caring for a sick baby at night.
Preventing RSV
- wash hands often, and ask visitors with colds to stay away from young babies
- avoid crowded places with newborns in RSV season
- ask your doctor about RSV antibody injections (such as nirsevimab) for your baby, or the RSV vaccine during pregnancy
- breastfeeding may offer some protection
When to talk to your doctor
- any breathing difficulty listed above
- fever in a baby under 3 months
- dehydration: fewer wet nappies, dry mouth or no tears
- your baby was premature or has a heart or lung condition and develops cold symptoms
- symptoms getting worse after 3 to 5 days
Frequently asked questions
How long is RSV contagious?
Usually 3 to 8 days, but young babies can spread it for up to 4 weeks.
Can babies get RSV more than once?
Yes, but later infections are usually milder.
How long does the cough last?
The cough can linger for 2 to 4 weeks even after other symptoms improve.
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Sources
- CDC: RSV in infants and young children; RSV immunization
- NHS: Bronchiolitis; RSV vaccine
- American Academy of Pediatrics, HealthyChildren.org: RSV
This guide is general information, not medical advice. If your baby has breathing difficulty, seek medical help straight away.