By: Flor M. Muñoz, MD, MSc, FAAP & Kristina A. Bryant, MD, FAAP
Flu—short for influenza—is an illness caused by a respiratory virus. The flu can spread rapidly through communities, as the virus is passed person to person.
When someone with the flu coughs or sneezes, the influenza virus gets into the air. Then, people nearby, including children, can inhale it through the nose or mouth.
The virus also can be spread when people touch a contaminated hard surface, such as a door handle, and then put their hands or fingers in their nose or mouth, or rub their eyes.
When is flu season?
The flu season usually starts in the fall and can last until the end of spring. Ideally, children should get an annual flu shot as soon as it is available, ideally no later than the end of October. (See "Which Flu Vaccine Should Children Get?")
When there is an outbreak or epidemic, usually during the winter months, the illness tends to be most frequent in preschool or school-aged children. Flu viruses are known to spread quickly among
college students and teens, too.
In the first few days of illness, the virus is easily transmitted to other children, parents and caregivers.
It is important for anyone age 6 months old and older to get the flu vaccine each year. Everyone age 6 months and older should also get COVID-19 vaccines. The COVID vaccine and flu vaccine can safely be given at the same time or at any time one after the other.
Flu symptoms include:
fever (usually above 100.4°F or 38°C)
Headache, body aches, and being a lot more tired than usual
Dry, hacking cough
Stuffy, runny nose
Some children may throw up (vomit) and have loose stools (diarrhea).
After the first few days of these symptoms, a sore throat, stuffy nose, and continuing cough become most evident. The flu can last a week or even longer. A child with a
common cold usually has only a low-grade fever, a runny nose, and only a small amount of coughing. Children with the flu—or adults, for that matter—usually feel much sicker, achier and more miserable than those with just a cold.
Kids with chronic health conditions at greater risk
Any child can develop severe, life-threatening influenza. Children who are at especially high risk for developing complications from the flu are those with an underlying chronic medical condition, such as lung, heart, or kidney disease, an immune system condition, cancer, diabetes, some blood diseases or conditions of the muscular or central nervous system.
These children may have more severe disease or complications. It is important for them to be vaccinated and, when possible, avoid other children with the flu or flu-like symptoms. Their pediatrician may suggest other precautions that should be taken.
If your child has any of these chronic health conditions and flu-like symptoms along with any difficulty breathing, seek medical attention right away. There can be serious complications, even death, from the flu, but thanks to the flu vaccine these are less common.
Children may benefit from extra rest and drinking lots of fluids when they get the flu.
If your child is uncomfortable because of a fever,
ibuprofen in doses recommended by your pediatrician for his age and weight will help him feel better. Ibuprofen is approved for use in children age 6 months and older; however, it should never be given to children who are
dehydrated or who are vomiting continuously.
It is extremely important never to give aspirin to a child who has the flu or is suspected of having the flu. Aspirin during bouts of influenza is associated with an increased risk of developing
Antiviral medicine for the flu: available by prescription
Your pediatrician can help decide whether or not to treat the flu with an
antiviral medicine. Antiviral medicine works best if started within the first one to two days of showing signs of the flu. However, in some children with increased risk for influenza complications, treatment could be started later.
Call your pediatrician within 24 hours of the first flu symptom to ask about antiviral medications if your child:
Has an underlying health problem like asthma or other chronic lung disease, a heart condition, diabetes, sickle cell disease, a weakened immune system, a neuromuscular condition such as cerebral palsy, or other medical conditions.
Is younger than 5 years old, especially if less than 2 years old.
Has symptoms that are not improving.
Is in contact with others who are at risk for complications of the flu.
How long does the flu last?
Healthy people, especially children, get over the flu in about a week, without any lingering problems. Talk with your child's doctor if you suspect a complication like ear pain, pressure in your child's face and head, or a cough and fever that will not go away.
When flu becomes an emergency
If your child has the flu and develops any of these symptoms, contact your pediatrician or seek immediate medical care.
Trouble breathing or unusually rapid breathing
Bluish lips or face
Ribs looking like they pull in with each breath
Muscle pain so severe that your child refuses to walk
Dehydration (no peeing for 8 hours, dry mouth, and no tears when crying)
While awake, your child is not alert or interacting with you
Fever above 104°F
In children less than 12 weeks, any fever
Fever or cough that seem to improve but then return or worsen
- Worsening chronic medical conditions, such as asthma
How to prevent the flu
Everyone needs the flu vaccine each year to update their protection and reduce te risk of serious complications. It is the best way to prevent getting the flu. Safe and effective vaccines are made each year.
The flu vaccine is especially important for:
Children, including infants born preterm, who are 6 months to 5 years of age
Children of any age with chronic medical conditions that increase the risk of complications from the flu
All contacts and care providers of children with high risk conditions and children under 5 years old
- People who are
pregnant, are considering pregnancy, have recently delivered, or are breastfeeding during the flu season. This is to protect the parent and the baby, which is important since newborns and infants under 6 months old are not able to receive their own vaccination.
- All health care workers
Both the inactivated (killed) vaccine, also called the "flu shot," given by injection in the muscle, and the live-attenuated
nasal spray vaccine, can be used for influenza vaccination this season. There is no preference for a product or formulation. Any of these vaccines should be given as available in your area.
The vaccine boosts your body’s immune system to protect you from the virus. This takes about two weeks after getting vaccinated. Getting vaccinated before the flu starts spreading around will keep your family healthy so they can continue to enjoy the activities that help them thrive.
Flu vaccine side effects
The flu vaccine has few side effects. The most common side effects from the flu shot are fever and redness, soreness or swelling at the injection site. The most common side effects from the nasal spray vaccine are runny nose, congestion and sore throat.
Children with egg allergies can receive the flu vaccine. Children with a previous allergic reaction after a dose of flu vaccine should be seen by an allergist. The allergist can help parents decide if their child should receive an annual flu vaccination.
About Dr. Muñoz
Flor Muñoz, MD, MSc, FAAP, is associate professor of Pediatrics and Infectious Diseases at Texas Children's Hospital and Baylor College of Medicine. She is a member of the American Academy of Pediatrics Section on Infectious Diseases.
About Dr. Bryant
Kristina A. Bryant, MD, FAAP, a pediatric infectious diseases specialist at the University of Louisville and Norton Children’s Hospital, is the lead for Red Book Online. She also is the immediate-past president of the Pediatric Infectious Diseases Society.