Flu in children and whether your child needs the flu vaccine every year

Flu (influenza) is more than a bad cold. It comes on suddenly with high fever and aches, and it can make babies and young children quite ill. A yearly flu vaccine from 6 months of age is the best protection, and vaccines given in pregnancy protect newborns. These are the flu questions Dr Dutta is asked most often in clinic.

Is it a cold or the flu?

Flu usually starts suddenly, with fever, body aches and tiredness. A cold creeps in slowly, with a runny nose and sneezing, and little or no fever.

US health guidance compares them like this:¹

• Start: flu is abrupt; a cold is gradual.
• Fever: common with flu, often lasting 3 to 4 days; rare with a cold.
• Aches: often severe with flu; slight with a cold.
• Headache: common with flu; rare with a cold.
• Cough and chest discomfort: can be severe with flu.

You cannot be sure from symptoms alone. A doctor can test a nose swab if the result would change treatment.

What are the symptoms of flu in babies and young children?

Common symptoms are fever or chills, cough, sore throat, runny or blocked nose, body aches, headache and tiredness.¹ Children are more likely than adults to have vomiting and diarrhoea.¹

Not every child with flu has a fever.¹ Babies cannot tell you they ache, so you may see:

• crankiness and crying that is hard to settle
• poor feeding
• more sleepiness than usual
• fast breathing

A baby under 12 weeks with any fever needs medical care straight away.¹

How long does flu last in children?

Fever with flu often lasts 3 to 4 days.¹ Most children feel better within a week, but a cough and tiredness can linger for another week or two.

What matters most is the direction of the illness. A child who slowly improves is on track. Watch out for one who gets better and then worse again, with fever or cough returning. This can mean a complication such as pneumonia or an ear infection, and US guidance lists it as a sign to get care straight away.¹

Which children are at high risk from flu?

Children under 5 years, and especially under 2 years, are at higher risk of serious flu complications. So are children of any age with long-term conditions such as asthma or diabetes.²

Other children Dr Dutta watches closely during flu season:

• babies born premature
• children with heart disease, kidney disease or sickle cell disease
• children with weak immunity, for example on cancer treatment or long-term steroids
• children with conditions of the brain, nerves or muscles that affect coughing or swallowing

If your child is in one of these groups, call your doctor early when flu symptoms start.

How do I care for a child with flu at home?

Rest, plenty of fluids, and paracetamol or ibuprofen if the fever makes your child miserable. Most healthy children recover at home.

• Offer small, frequent drinks: breast milk, formula, water, ORS, daab (coconut water), dal water or soup.
• Do not worry if appetite drops for a few days, as long as your child drinks and passes urine.
• Clear a blocked nose with saline drops before feeds.
• Antibiotics do not work against the flu virus.
• Do not give cough and cold syrups to young children.
• Do not give aspirin to children.

Keep the sick child away from newborn siblings and elderly grandparents if you can, and wash hands often.

Does my child need Tamiflu (oseltamivir)?

Not every child with flu needs it. It is recommended for children who are in hospital, very unwell, getting worse, or at high risk of complications, and should then be started as soon as possible.³

The American Academy of Pediatrics says that for these children, treatment should start even if they have been ill for several days.³ For other children, it is an option your doctor may offer.³

A pooled analysis of 5 trials in children with confirmed flu found oseltamivir shortened the illness by about 18 hours on average, and cut the risk of ear infection by about a third. Vomiting was the main side effect.⁴ It is a prescription medicine. Give it only on your doctor's advice and at the dose they work out for your child's weight.

Can Tamiflu prevent flu in my child?

Sometimes. Doctors may give it to prevent flu in a high-risk child who has been exposed and has not been vaccinated, or who may not respond well to the vaccine.³

It is not a substitute for the vaccine. For most healthy children who are exposed, the usual advice is to watch for symptoms and see a doctor early if they appear.

From what age can my baby get the flu vaccine?

From 6 months of age. The American Academy of Pediatrics recommends a flu vaccine every year for all children from 6 months onwards, unless there is a medical reason not to.³

Babies under 6 months are too young for the vaccine, yet very young babies can become seriously ill with flu. They are protected best by vaccinating the mother in pregnancy and everyone who lives with the baby.

The Indian Academy of Pediatrics includes flu vaccine in its schedule, and in its 2025 update advised moving from four-strain to three-strain vaccines.⁵ Ask your paediatrician which one is available.

Why does my child need two doses of flu vaccine the first time?

A young child's immune system needs two doses to build good protection the first time. Once your child has had two doses in total, one dose a year is enough.²

US guidance says children aged 6 months to 8 years getting the flu vaccine for the first time need two doses, given at least 4 weeks apart.² The first dose should be given as soon as the vaccine is available.² That way the second dose is done before flu season peaks.

A child aged 6 months to 8 years who has only ever had one dose needs two doses again the next season, 4 weeks apart.² Ask your doctor to check the record.

Why does my child need the flu vaccine every year?

Because flu viruses keep changing, and protection from the vaccine fades over months. Each year's vaccine is updated to match the strains expected to spread.

The vaccine recipe is reviewed often. In 2025, for example, the Indian Academy of Pediatrics advised replacing four-strain with three-strain vaccines.⁵ Last year's dose may not cover this year's strains.

When is the best time to get the flu vaccine in Kolkata?

Before the monsoon, ideally in April or May. In Kolkata, flu usually peaks in July to September, with the rains.⁶

A study of flu across 10 Indian cities found peaks during the monsoon months in Kolkata, Delhi, Pune and several other cities. The authors suggested that cities with a monsoon peak would benefit from vaccinating in April and May.⁶ Chennai peaks later, in October and November, and Srinagar in winter.⁶

If you missed that window, getting the vaccine late is still better than not at all.

Can the flu vaccine give my child flu?

No. The injected flu vaccine does not contain live virus, so it cannot cause flu.

Some children get a sore arm or thigh, a mild fever, or feel off-colour for a day or two. These are signs the immune system is responding. A cold that happens to start the same week is a coincidence, because many viruses circulate in the rainy season.

Tell your doctor before the vaccine if your child had a severe allergic reaction to a previous flu vaccine.

Should I get the flu vaccine in pregnancy to protect my baby?

Yes. A flu vaccine in pregnancy protects you and passes antibodies to your baby, covering the first months before the baby can be vaccinated.

A randomised trial of 340 mothers in Bangladesh found that vaccinating mothers in pregnancy reduced confirmed flu in their babies by 63% up to 6 months of age. It also prevented about a third of fever with breathing illness in both mothers and babies.⁷

Ask your obstetrician about the flu vaccine during your pregnancy.

Why is the whooping cough vaccine given in pregnancy?

Because whooping cough (pertussis) hits babies under 3 months hardest, and they are too young to be fully protected by their own vaccines. A vaccine in pregnancy passes antibodies across the placenta.

When England started vaccinating pregnant women, cases in babies under 3 months fell sharply. The vaccine was about 91% effective in protecting babies of this age, and the youngest babies still had the highest rates of disease.⁸

Whooping cough starts like a cold, then causes long coughing fits. Young babies may not whoop. They may go blue, stop breathing for a moment, or vomit after coughing. Any baby with these signs needs urgent care.

Why does my child keep getting sick after starting daycare?

Because daycare brings many young children together, and each new virus is new to your child. This is common and usually settles with time.

A Dutch study of over 2,200 children found that those who started daycare in the first year had more colds and ear infections early on, but fewer after age 4. Over six years, the total number of infections was about the same.⁹

A yearly flu vaccine, good handwashing at daycare and keeping sick children at home all help.

When can my child go back to school or daycare after flu?

Keep your child at home while the fever lasts, and let the school or daycare know about the illness. UK guidance gives this advice for children under 5.¹⁰

For children of any age, Dr Dutta suggests waiting until your child has had no fever for a full day without fever medicine, and is eating and playing again. Sending a child back with a fever hidden by paracetamol spreads flu to others.

When should I take my child with flu to a doctor or hospital?

Get medical care straight away if your child has any of these warning signs:¹

• breathing fast or with difficulty
• the skin between the ribs sucking in with every breath
• a blue tinge to the lips or face
• signs of dehydration, such as a dry mouth, crying without tears, or no urine in 8 hours
• being unusually drowsy or not responding when awake
• a seizure (fit)
• fever above 104 degrees F (40 degrees C) that does not come down with fever medicine
• any fever in a baby younger than 12 weeks
• fever or cough that improves and then returns or worsens
• severe muscle pain, so the child refuses to walk
• worsening of a long-term condition such as asthma