Flu (influenza): Prevention and risks

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How the flu spreads

The flu is an infection of the nose, throat and lungs. It is caused mainly by 2 types of viruses:

  1. Influenza A
  2. Influenza B

The flu spreads very easily from person to person. Even before you notice symptoms, you may spread the virus to others. If you have the virus, you can spread it by:

  • talking
  • sneezing
  • coughing

These actions release tiny droplets that contain the flu virus into the air.

You can become infected if these droplets land on your:

  • eyes
  • nose
  • mouth

Infection can also happen if you touch any of these body parts after touching surfaces contaminated by infected droplets. Common contaminated surfaces include:

  • phones
  • doorknobs
  • someone's hands
  • television remotes

Preventing the flu

The flu shot is safe and is the best way to prevent the flu. You cannot get the flu from the flu shot. Most people do not have any side effects. Severe reactions are very rare.

Get the flu shot

Everyone 6 months and older should get the flu shot. Getting a flu shot is a simple action that can save lives by:

  • preventing you from getting very sick
  • protecting you if you are exposed to the virus
  • helping protect other people
    • because you are less likely to spread the virus

In addition to getting the flu shot, you can also protect yourself and those around you by:

  • not touching your face
  • washing your hands often
  • coughing and sneezing into the bend of your arm, not into your hand
  • cleaning and disinfecting surfaces that a lot of people touch, such as:
    • phones
    • doorknobs
    • television remotes

If you do get sick, stay home. Avoid close contact with other people until you feel well enough to get back to your usual day-to-day activities. This will help prevent the spread of the flu.

When the flu is a risk

In Canada your risk of getting the flu is higher in the:

  • late fall
  • winter

Your risk is lower the rest of the year.

Who is most at risk

Everyone is at risk of getting the flu. The flu is among the 10 leading causes of death in Canada. Each year in Canada, the flu causes an estimated:

  • 12,200 hospital stays
  • 3,500 deaths

Some people are at a higher risk of flu-related complications. These include:

  • People with health conditions; These conditions can affect a person's immune system and can make it harder to fight off infections. Getting the flu can also worsen these pre-existing conditions such as:
    • cancer and other immune compromising conditions
    • diabetes
    • heart disease
    • lung disease
    • anemia
    • obesity
    • kidney disease
    • neurologic or neurodevelopment conditions
    • children up to 18 years of age undergoing treatment for long periods with acetylsalicylic acid (ASA)
  • People 65 years and older; The immune system changes with age and this can make it harder for the body to fight off infections. People over the age of 65 are also more likely to have health conditions which can worsen if they get the flu.
  • People who live in nursing homes or other long-term care facilities; The flu spreads quickly, especially in communal spaces. Residents are also more likely to have health conditions which can worsen if they get the flu.
  • Children under 5 years of age; Because of their age, their immune system is still building immunity to fight off serious infections.
  • Pregnant women; During pregnancy, the body goes through many changes that can affect the immune system, heart and lungs. These changes can make it harder for the body to fight off infections.
    • Women who get the flu shot during pregnancy pass on immunity to their baby. This is especially important, as babies younger than 6 months can't get vaccinated against the flu. Getting your flu shot can help protect your baby from the flu after birth.
  • Indigenous peoples; There is a higher risk of flu-related complications and/or hospitalization for Indigenous peoples. This is a result of multiple factors, including a high occurrence of chronic health conditions, reduced access to health care, and other social and environmental factors.

Some people are more likely to spread the flu to those at high risk of complications. They include:

  • caregivers
  • child care providers
  • healthcare providers
  • family and other household members
  • those who provide services in closed or relatively closed settings to people at high risk, such as crew on a ship

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