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Flu (Influenza)


The flu is a respiratory infection that is spread easily. It is caused by the influenza virus.

This virus circulates each year in Quebec and elsewhere in the world. In Quebec, it especially spreads during the end of the fall to the beginning of the spring.

The duration of the flu season may vary. As such, it may start earlier or later and last shorter or longer depending on the year.


Flu symptoms that set in suddenly, as well as their severity, can vary depending on age and health condition. The main symptoms are the following:

  • Muscle pain
  • Fatigue
  • Sudden fever between 38 °C and 40 °C (100,4 °F and 104 °F)
  • Acute general discomfort lasting several days
  • Cough
  • Headache
  • Irritated or sore throat

Children can also experience nausea, vomiting, diarrhea and abdominal pains.

Older people may feel weak and disoriented without showing other symptoms.

Flu is often confused with other respiratory infections such as the cold. To learn more, go to the Differences between Flu and Cold page.

When to Seek Medical Help

Generally, the flu can be treated at home. In certain cases however, you must see a doctor.

If you are among people most at risk of complications and have flu-like symptoms, call Info-Santé 8-1-1. A nurse will evaluate your health and make recommendation based on your condition.

Same Day Consultation

You should seek medical help the same day if you have flu-like symptoms and also one of the following:

  • Shortness of breath
  • Difficulty breathing
  • Pain when breathing

Immediate Consultation at an emergency room

You must go to emergency immediately if you have flu-like symptoms and also one of the following:

  • Difficulty breathing that persists or increases suddenly
  • Blue lips
  • Difficulty moving
  • Significant stiffness of the neck
  • Drowsiness, difficulty staying awake
  • Confusion, disorientation
  • Seizures (body stiffens and muscles contract in a jerky and involuntary manner)
  • No urine output for 12 hours

If your child has a fever and appears very sick, lacks energy and refuses to play, promptly take them to a doctor.

If you require immediate help to get to emergency, call 9-1-1.


Most people in good health get better from the flu by themselves after 5 to 7 days. You should get good rest and eat according to your appetite.

However, coughing and fatigue may last for 2 weeks or even longer.

You may relieve symptoms of the flu by taking the following measures:

Drink much liquids often

If you have a fever, your body naturally loses a lot of fluid, especially through sweating. It is therefore important to drink a lot and often.

  • Preferably drink cold or hot liquids: water, milk, juice, broth
  • Avoid alcoholic beverages or caffeinated drinks such as coffee, tea and energy drinks. As these drink make you urinate, they increase loss of fluid

Use medication according to instructions  

In the absence of complications or risk factors, treatment of the flu requires no prescription medication. However, to relieve fever and pain, you may take over-the-counter medicine such as acetaminophen, Tylenol® for example, and ibuprophen, Advil® for example.

Avoid taking medication that includes identical ingredients at the same time. For instance, do not take Tylenol® and Tylenol® Sinus together because both these medicines contain acetaminophen.

In certain cases, your doctor may prescribe antiviral medicine to reduce the duration and severity of your symptoms. This type of medication is most effective when taken at the onset of an infection.

Children and Adolescents

If your child is over 3 months old and has a fever, you may give them acetaminophen such as Tylenol®, following instructions given and according to your child’s weight.

Avoid giving children and adolescents acetylsalicylic acid such as aspirin. Such medication can lead to a serious disease of the brain and liver known as ‘Reye's Syndrome’ in children and adolescents with the flu.


The flu can lead to certain complications, including:

  • Dehydration due to sweating caused by fever
  • Pneumonia
  • Bronchitis
  • Sinusitis

For people considered more vulnerable to sickness, certain complications can lead to hospitalisation or even death.

People most at Risk of Complications

People most at risk of complications are the following:

  • Children less than 2 years old
  • People with certain chronic diseases
  • Healthy pregnant women during their 2nd and 3rd
  • Pregnant women with certain chronic diseases, throughout pregnancy
  • People with a weakened immune system
  • People aged 60 years and over


The flu virus lives best in fresh and dry areas. It can live up to 2 days on contaminated objects or up to 5 minutes on skin.  

The flu virus is very contagious. It is spread quickly from person to person in the following ways:

  • By droplets sprayed through the mouth or nose by an infected person when they cough or sneeze
  • By direct contact with secretions from the nose or throat from a person with the flu, when kissing for instance
  • When you bring your hand to your nose, mouth or eyes after shaking the hand of someone infected or touching contaminated objects

A person infected with flu virus may be contagious:

  • 24 hours before showing symptoms
  • Up to 7 days after onset of symptoms, and sometimes even a bit longer.

Young children and seniors can be contagious for up to 14 days following onset of symptoms.

If you have the flu, avoid direct contact as much as possible with people most at risk of complications. This way, you reduce the risk of transmitting to them the illness.

Protection and Prevention

The best way to protect yourself from complications of the flu is through vaccination.

Certain protection and cleanliness measures can also help prevent transmission of the flu.

At all times

If you have the flu

  • Stay at home as soon as you notice symptoms of the flu. Unless otherwise advised by a doctor, home is the best place for treatment. By staying at home, you limit contact with other people or with other infections that may cause complications. You also limit transmission of the virus
  • Follow advice for Coughing or Sneezing Without Contaminating 

Last update: September 24, 2015 1:59 PM

The information on this website by no means replaces the advice of a health professional. If you have questions regarding your health, contact Info-Santé 8-1-1 or see a health professional.

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