At a glance
- Flu starts suddenly, 1 to 4 days after catching it, with fever, aches, cough and tiredness.
- Some children with flu never get a fever, and some vomit or have diarrhea.
- Higher risk: under 5 (most of all under 2) or asthma, diabetes, or heart or lung disease.
- Antiviral medicine such as oseltamivir (Tamiflu) works best when started within 2 days of the first symptom.
- Never give aspirin to a child with flu; it is linked to Reye syndrome.
- Call 911 for blue or gray lips, a hard struggle to breathe, a seizure, or a child who is not alert.
- Everyone 6 months and older should get a flu vaccine every year.
Flu symptoms in children
Flu usually hits fast: a child can seem fine in the morning and have a high fever, chills and body aches by evening.
A dry cough, sore throat, headache, stuffy nose and unusual tiredness are common. Flu usually feels much worse than a cold.
- Some children vomit or have diarrhea, and some never run a fever, so no fever does not rule flu out.
- Healthy children usually recover in about a week, though cough and tiredness can hang on longer.
How flu usually runs in a child
- 1 day beforeYour child can already spread flu before feeling sick.
- Days 1–3Sudden fever, aches and cough; the most contagious days. Antivirals help most if started in the first 2 days.
- Up to day 7Still able to spread the virus; young children may stay contagious longer.
- About 1 weekMost healthy children are better; a cough or tiredness can last longer.
Flu warning signs: when to get help
- Call 911 or your local emergency number for blue or gray lips or face, a hard struggle to breathe, a seizure, or a child who is not alert or is hard to wake.
- Get care right away for fast breathing, ribs pulling in with each breath, chest pain, or muscle pain so bad your child will not walk.
- Get care right away for dehydration: very little urine, a dry mouth or crying without tears.
- Call the doctor for a fever above 104°F (40°C), or any fever in a baby younger than 12 weeks.
- Call if fever or cough gets better and then returns or worsens, or if asthma or another long-term condition flares.
Flu in a child: when to get help
- Call 911 nowBlue or gray lips, a hard struggle to breathe, a seizure, not alert or hard to wake.
- Get seen nowFast breathing, ribs pulling in, chest pain, refusing to walk, very little urine or no tears.
- Baby under 12 weeksAny fever means a doctor's check today.
- Call within 24 hoursUnder 5 or a long-term condition: ask about antiviral medicine. Also call for fever above 104°F (40°C).
- Care at homeDrinking, alert between fevers, breathing easily: rest, fluids, fever medicine if needed.
Antiviral medicine (Tamiflu): who needs it
Antiviral medicine does not cure flu, but it can shorten the illness and lower the chance of serious problems.
- CDC and AAP advise it for any child with flu who is very sick, getting worse or in the hospital.
- It is also advised for higher-risk children: under 5 years, or any age with asthma, diabetes, or heart or lung disease.
- It works best when started within 2 days of the first symptom, but children can still benefit if it starts later.
- If your child is in a higher-risk group, call the doctor within 24 hours of the first symptom.
- The options are oseltamivir (Tamiflu), zanamivir, peramivir and baloxavir; the doctor chooses by age and health.
- Antibiotics do not work against flu viruses.
Caring for a child with flu at home
- Let your child rest and offer plenty of fluids through the day.
- For fever or aches, give acetaminophen, or ibuprofen from 6 months of age, at the dose for your child's age and weight.
- Do not give ibuprofen to a child who is dehydrated or keeps vomiting.
- Never give aspirin or products that contain it; with flu it can cause Reye syndrome, a rare but serious illness of the liver and brain.
- A sick adult should stay away from babies when possible, wash hands before caring for them and cover coughs.
How flu spreads and going back to school
- Flu spreads through coughs, sneezes and hands that touch shared surfaces.
- A child can spread it from 1 day before symptoms until about 5 to 7 days after, and young children sometimes longer.
- CDC advises staying home until symptoms are improving overall and there has been no fever for 24 hours without fever medicine.
- For the next 5 days, keep up hand washing, cover coughs and keep extra distance from babies and people at high risk.
Flu vaccine for children
- Every child 6 months and older needs a flu vaccine each year, as soon as it is offered in the fall.
- Children 6 months through 8 years who have had fewer than 2 flu vaccine doses before need 2 doses, 4 weeks apart.
- The nasal spray is an option for healthy children 2 years and older; the shot can be given from 6 months.
- Children with an egg allergy can get the flu vaccine with no extra steps.
- Protection takes about 2 weeks to build. Ask your child's doctor about this season's vaccine.
Common questions
How long is a child with flu contagious?
The first 3 days of illness carry the most risk. Young children can keep shedding the virus for more than a week.
Does my child need Tamiflu for the flu?
It matters most for children who are very sick or in a higher-risk group. Ask the doctor early, since the medicine helps most in the first days.
When can my child go back to school after the flu?
Once a full day has passed with no fever, without help from fever medicine, and your child is feeling better overall.
Can a child have the flu without a fever?
Yes. Cough, aches, tiredness or an upset stomach may be the only clues.
Can my child get the flu shot with an egg allergy?
Yes, and no special precautions are needed. Only a past allergic reaction to a flu vaccine calls for an allergist's advice first.
Why does my young child need two flu vaccine doses?
A young child's first flu vaccine needs a second dose 4 weeks later to reach full protection.
Sources
- AAP — The Flu: What Parents Need to Know
- AAP — Which Flu Vaccine Should Children Get This Season?
- CDC — Treatment of Flu in Children
- CDC — How Flu Spreads
- CDC — Preventing Spread of Respiratory Viruses When You're Sick
Written for Pedemy in our own words from the sources above; checked October 2026. For education only, not medical advice. Pedemy is independent and not affiliated with or endorsed by the organizations cited.