What is influenza?
Influenza (or “flu”) is a respiratory infection caused by influenza virus. A virus is a germ that makes people sick.
Influenza outbreaks happen every year, usually between November and April. Because influenza viruses change – often from year to year – people don’t stay immune for very long. That’s why people can catch the flu more than once. The term “seasonal flu” is used for the influenza viruses that spread every year.
From time to time, there is a major change in the influenza virus, and no one is immune. When this happens, many people of all ages around the world become sick with the flu within a few months. This is called a pandemic. Pandemics have occurred in 1889, 1918, 1957 and 1968, and 2009 (H1N1).
How does influenza spread?
Influenza viruses are found in the nose and throat. Children can catch influenza from siblings, parents, other family members, playmates or caregivers.
Germs usually spread in one of three ways:
- Direct contact —such as kissing, touching or holding hands—with an infected person. If you have a virus, you will have germs in your nose, mouth, eyes or on your skin. By touching other people, you can pass on the virus.
- Indirect contact means touching something—a toy, doorknob or a used tissue—that has been touched by an infected person and now has germs on it. Some germs, like the ones that cause colds and diarrhea, can stay on surfaces for many hours.
- Some germs spread through the air when a person coughs or sneezes. Droplets from the cough or sneeze may reach another person’s nose or mouth.
How do I know if my child has influenza?
The flu strikes more quickly than a cold, and makes people feel worse. Children with colds usually have energy to play and keep up their daily routines. Children with influenza are usually in bed.
Typical influenza symptoms include:
- sudden fever,
- chills and shakes,
- muscle aches,
- extreme fatigue,
- dry cough and sore throat and,
- loss of appetite.
Children with the flu may have many of the same symptoms as adults, but there can be differences:
- Newborns and babies may have a high fever that can’t be explained, and no other signs of sickness.
- Young children usually have temperatures over 39.5°C and may have febrile seizures (convulsions).
- Stomach upset and pain, vomiting, and diarrhea are common in younger children. Earaches and red eyes are also common.
- In some cases, muscle inflammation can lead to severe leg or back pain.
Can the flu cause any other complications?
Most healthy people recover from the flu without any serious problems. Fever and muscle aches usually last only 2 to 4 days, but cough and tiredness can continue for 1 to 2 weeks or more.
In young children, flu can cause croup (an infection of the throat and vocal cords causing horseness, barking cough, noisy breathing), pneumonia (lung infection) and bronchiolitis (infection of the tiny airways that lead to the lungs causing wheezing and difficulty breathing).
Influenza can lead to bacterial infections of the ear (otitis), lung (pneumonia) or sinuses (sinusitis).
Influenza is more severe in children under 2 years of age and in children with certain chronic conditions such as heart or lung conditions.
In rare cases, influenza can affect the brain, heart or weaken the immune system.
When should I call my doctor?
Call your doctor or take your baby to an emergency department if your baby is *under 3 months of age* and:
- is having trouble breathing,
- is not eating or is vomiting, or
- has a fever (rectal temperature of 38.5°C or higher).
Call your doctor or take your child to an emergency department if your child is:
- breathing rapidly or seems to be working hard to breathe,
- having chest pain, or is coughing up bloody sputum (phlegm or saliva);
- coughing so bad that he is choking or vomiting,
- drinking very little fluid and has not urinated (peed) at least every 6 hours when awake,
- vomiting for more than 4 hours, or has severe diarrhea,
- much more sleepy than usual, doesn’t want to feed or play, or is very fussy and cannot be comforted,
- not feeling better after 5 days and still has a fever, or was feeling better and suddenly develops a new fever, or
- showing signs of the flu and has a serious chronic illness.
Take your child immediately to a hospital emergency department or call 911 if your child:
- has severe trouble breathing or blue lips;
- is limp or unable to move;
- is hard to wake up or does not respond;
- has a stiff neck;
- seems confused; or
- has a seizure (convulsion).
What can I do if my child has influenza?
- Keep your child as comfortable as possible. Offer plenty of fluids and small, nutritious meals.
- If he has fever, dress him in lightweight clothing and keep the room temperature around 20°C.
- Check your child’s temperature. To ease pain, aches or a fever with a temperature greater than 38.5°C, use acetaminophen. Ibuprofen may be used for children over 6 months old. Unless your doctor says otherwise, give the dose recommended on the package every 4 hours until the child's temperature comes down. Don’t give acetylsalicylic acid (ASA [eg, Aspirin])—or any medicine containing it—to children and teenagers with colds because it can lead to brain and liver damage (Reye syndrome).
- Don’t give over-the-counter (OTC) cough and cold medicines (which don’t need a doctor’s prescription) to children younger than 6 years old unless your doctor prescribes them.
- Talk to your doctor or pharmacist before giving OTC drugs to children or to anyone taking other medicines or with a chronic illness. Read label instructions carefully. Do not give more than is recommended.
- Coughing helps clear mucus from the chest. Many OTC cough and cold products contain drugs to ease coughing. Usually they include dextromethorphan (also called DM) and/or diphenhydramine. Most studies of these drugs have been done in adults. The few that have been done in children show no benefit.
- Gargling with warm water will ease a sore throat. For children 3 years or older who can safely suck on hard candy without choking can use sugarless hard candy or lozenges containing honey, herbs or pectin. Throat lozenges containing medications that numb the throat (dyclonine, benzocaine, hexylresorcinol, menthol and phenol) should not be used by young children because they can make it hard for them to swallow.
If your child has lung or heart disease, an illness that affects the immune system or some other chronic condition that requires regular medical attention and you think your child may have influenza, call your doctor right away. Your doctor may prescribe an antiviral drug.
Mantadine (Symmetrel), oseltamivir (Tamiflu) and zanamivir (Relenza) are antiviral medications that can fight influenza. These drugs may also be prescribed for healthy people with severe influenza. They should be taken within 48 hours of the first symptoms to be most effective.
How can I prevent the spread of influenza?
- Influenza can be prevented through immunization. Children over 6 months old should get a flu shot each year. The vaccine is especially important for children who are at high risk of complications from the flu (children under 2 years old and children with chronic conditions). If there are children younger than 2 years old or someone with a serious chronic condition in your home, everyone living in the house should get a flu shot. This is especially important if there are children under 6 months old in the home, since babies this age can’t get the flu shot themselves and could become infected if a family member gets the flu.
- Babies under 6 months old cannot get the vaccine, as it does not work in this age group.
Hand washing is the most important way to reduce the spread of viruses:
- Wash your hands after coughing, sneezing or wiping your nose.
- Wash your hands after being in contact with someone who has a respiratory infection.
- Wash your own hands and your child’s hands after wiping your child’s nose.
- When water and soap are not available, use premoistened hand wipes or alcohol-based hand rinses. Keep hand rinses out of your child’s reach because they may be harmful if swallowed.
- Keep babies under 3 months old away from people with colds, if possible.
- Teach your children to cover their nose and mouth with tissues when they sneeze or cough, or to cough into their upper sleeve or elbow.
- Avoid sharing toys that young children place in their mouths until the toys have been cleaned.
- Avoid sharing cups, utensils or towels until they have been washed.
- If your child attends daycare, tell the caregiver about any symptoms and ask if your child should stay home that day.
- Make sure your child receives all of the recommended vaccines. They will help prevent some of the complications, such as bacterial infections of the ears or lungs.
Reviewed by the following CPS Committees:
Infectious Diseases and Immunization Committee
Last updated: December 2010