Influenza (Flu): An Overview

What is influenza?

Influenza (flu) is a lung infection caused by a specific influenza virus. People  can get the flu at any time of year, but it is more common in the fall and winter.

Common symptoms of the flu

People who get the flu usually have some or all of the following symptoms:

Most of these symptoms usually last for 2 to 7 days. The cough and weakness can last for up to 6 weeks. This can make exercise and even day-to-day activities difficult.

The flu can be serious for some people

Most people who get the flu will not get seriously ill. But the flu can be more serious for some people. Typically, those most at risk are in one of these groups:

  • people 65 years of age or older
  • people living in long-term care facilities such as a nursing home, a home for the aged, or a chronic care hospital
  • people with chronic heart, lung, or kidney disease
  • people with diabetes, cancer, immune system problems, or sickle cell anaemia
  • children and teenagers aged 6 months to 18 years who have been treated with ASA (acetylsalicylic acid or Aspirin) for long periods
  • children under 2 years of age
  • people who have trouble clearing mucus from their nose and throat because of weakness or underlying illness

Anyone who lives or works with people from these groups should be immunized with the flu vaccine (shot). That way, people from these high-risk groups are less likely to be infected with the flu. The flu vaccine is discussed further down the page.

Treating the flu

Usually, treatment is focused on the symptoms the person is feeling. For example, if your child has a fever, you can give him acetaminophen​ (Tylenol) to reduce fever.

There is also a medicine available to help treat flu in patients 1 year old or older. Contact your child's doctor for more information.

How the flu spreads

The flu spreads very easily from an infected person to others through coughing and sneezing. It is also spread by touching objects after someone with the flu has touched them.

If your child has the flu in the hospital

Your child will be placed in a single room and will not be able to visit the playroom until they are feeling better. Ask the Child Life Specialist to bring toys and supplies to your room.

Hospital staff will be wearing a mask, eye protection, gloves, and gowns when they visit. 

Wash your hands often, either with alcohol-based hand rubs or soap and water, before and after touching your child and before leaving your child's room. Hospital staff should wash their hands as well.

If you or anyone else who has visited becomes ill with symptoms of the flu, let your child's doctor or nurse know. 

Preventing the flu

The following are ways to avoid getting the flu:

  • Wash your hands well. This can help prevent you from catching or spreading the flu. This is very important in hospitals, but it is true in other places as well.
  • Get a flu shot every year.

If you have the flu, you should do the following things to avoid spreading it:

  • Always cover your mouth or nose with a tissue when you cough or sneeze. Throw away the tissue. Then wash your hands. These steps will help prevent spreading the flu and other respiratory viruses.
  • Do not visit the hospital when you are ill with symptoms of the flu. No one who is ill should visit a patient in the hospital, even if they are a relative.

The flu shot

The influenza vaccine (flu shot) is made from pieces of killed and/or live altered flu viruses. It contains 3 different types of flu viruses. A person who receives the flu shot develops immunity for the types of flu in the vaccine. "Immunity" means the body builds up protection against the virus.

The body needs about 2 weeks after the shot to build up protection against the virus. This protection lasts for about 6 months.

The flu shot will not protect against other viruses.

A flu shot every year

People need a new flu shot every year. The flu virus changes each year, so a different vaccine has to be used each year too. Doctors and scientists find out the types of flu virus that are circulating around the world. The vaccine is then made to protect against the types that are most likely to occur each year.

Most people can get a flu shot

The flu shot is free to people living in Ontario. Anyone older than 6 months of age should have the flu shot unless there is a reason not to. Ask your child's doctor if your child can get the flu shot.

What is pandemic flu?

A flu pandemic is an outbreak of the flu virus that spreads quickly around the world. Flu pandemics happen when a new type of flu develops. Because it is new, people have little or no immunity against it. This means that all people could be at risk for serious illness.

Avian influenza (bird flu) is an example of a new type of flu. It has spread between birds and has now infected humans. So far, there is little spread between humans. If human-to-human spread becomes common and avian flu is spread worldwide, then a pandemic would be declared.

Protecting your family against pandemic flu

If a pandemic is declared, pay attention to public health messages about what to do and who is at risk. In the meantime:

  • Get a flu shot every year.
  • Wash your hands often.
  • Cover your nose and mouth when you cough or sneeze.
  • If you are sick, do not go to work or to school.

More about protecting your family from pandemic flu

There are further steps you and your family can take to help protect yourself from pandemic flu.

For more information about flu and preparing for a flu pandemic, go to:

Laurie Streitenberger, RN, BSc, CIC
Anne Matlow, MD, FRCPC