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Flu (Influenza)


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

This virus circulates each year in Québec and elsewhere in the world. In Québec, it mostly 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, which appear suddenly, and their severity, can vary depending on age and health condition. The main symptoms are the following:

  • Sudden fever between 38 °C and 40 °C (100,4 °F and 104 °F)
  • Sudden cough
  • Sore throat
  • Muscle or joint pain
  • Extreme fatigue
  • Headache

Symptoms such as nausea, vomiting, diarrhea and abdominal pain may also be experienced. These symptoms are most common in children.

Seniors may feel weak and sometimes disoriented without showing other symptoms.

The flu is often confused with other respiratory infections such as the cold. To learn more, read Differences between Flu and Cold.

When to Seek Medical Help

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

Same Day Consultation

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

  • Increasing or persistent pain when breathing
  • A rising fever, or one that has lasted for over 5 days

If symptoms worsen or do not improve after 7 days, you should also consult a doctor the same day.

Immediate Consultation at an Emergency Room

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

  • Breathing difficulty that persists or worsens
  • Blue lips
  • Intense chest pain
  • Intense headache that persists or worsens
  • Drowsiness, difficulty staying awake, weakness
  • Confusion, disorientation
  • Seizures (body stiffens and muscles contract in a jerky and involuntary manner)
  • No urination for 12 hours, excessive thirst

If your baby is less than 3 months old and has a fever, bring him or her to emergency immediately.

If your child has a fever and appears very sick, lacks energy and refuses to play, bring him or her to a doctor immediately, or call Info-Santé 8-1-1.

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

Call Info-Santé 8-1-1

Some situations require you to be evaluated by a nurse who can offer specific advice regarding your condition. The nurse can also assess whether or not you should see a doctor immediately.

You should call Info-Santé 8-1-1 if you or your child are in one of the following situations:

  • You are short of breath
  • You have difficulty breathing
  • You are unsure whether or not to see a doctor


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.

Coughing and fatigue may last for 2 weeks or even longer.

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

Drink a lot of liquids and 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 him or her 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
  • Otitis

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

People most at risk of complications

The following people are most at risk of complications:

  • Children younger than 5 years old
  • People with chronic diseases
  • Pregnant women
  • Women who gave birth in the last 4 weeks
  • People aged 65 years and over

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


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 the illness to them.

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: October 6, 2016 3:55 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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