Flu (influenza)


The flu is a respiratory infection that spreads very easily. It is caused by influenza viruses.

The flu circulates each year in Québec and around the world. In Québec, it circulates mainly from late fall to early spring.

The duration of the flu season can vary. It can start earlier or later and be shorter or longer depending on the year.


Flu symptoms and their severity can vary with age and health status. The main symptoms are as follows:

  • Sudden fever, between 39°C and 40°C (102°F and 104°F)
  • Sudden cough
  • Sore throat
  • Muscle or joint pain
  • Extreme fatigue
  • Headaches

Symptoms can also include nausea, vomiting, diarrhea and abdominal pain. These symptoms are more common in children.

In older adults, feeling weak and confused sometimes may be the only symptoms.

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

When to see a doctor

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

Same day consultation

You must see a doctor on the same day if you have flu symptoms and also one of the following symptoms:

  • Persistent or increasing pain when breathing
  • A fever that is getting worse or has lasted for over 5 days

If your symptoms get worse or do not improve after 7 days, you must also see a doctor.

You can get a consultation at a resource near you, for example at a medical clinic or at a CLSC. To learn more or to find a resource, go to the page Finding a Resource Offering Medical Consultation On The Same or Next Day This hyperlink will open in a new window..

Immediate consultation at an emergency room

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

  • Persistent or increasing difficulty breathing
  • Blue lips
  • Severe chest pain
  • Persistent or increasing severe headache
  • Drowsiness, difficulty staying awake, weakness
  • Confusion, disorientation
  • Seizures (the body stiffens and muscles contract in a jerky and involuntary manner)
  • No urination for 12 hours, intense thirst

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

If your child has a fever and appears very sick, lacks energy and refuses to play, bring him or her to a doctor quickly or call Info-Santé 811.

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

Call Info-Santé 811

Some situations require you to be assessed by a nurse who can give you specific advice about your situation. She can also tell you if you should see a doctor quickly.

You should call Info-Santé 811 if you or your child are in one of the following situations:

  • you are short of breath;
  • you do not know if you must see a doctor.


Most healthy people recover from the flu by themselves after 5 to 7 days. You must get plenty of rest and eat according to your appetite.

Coughing and fatigue may, however, last up to 2 weeks or even longer.

You can relieve flu symptoms by taking the following measures:

Drink plenty lot of liquids often

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

  • Drink fluids, such as water, milk, juice or broth.
  • Avoid alcoholic beverages or caffeinated drinks such as coffee, tea and energy drinks. These drinks make you urinate, increasing fluid loss.

Use medications as directed

In the absence of complications or risk factors for complications, you do not need prescription medication to treat the flu. However, to relieve the fever and pain, you can take over-the-counter medications such as acetaminophen, for example Tylenol®, or ibuprophen, for example Advil®.

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

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

Children and teenagers

If your child is over 3 months old and has a fever, you can give him or her acetaminophen, for example Tylenol®, making sure you follow the instructions that come with the product and based on your child’s weight.

Avoid giving children and teenagers acetylsalicylic acid, for example aspirin. This medication could cause a serious brain and liver disease known as “Reye's syndrome” in children and teenagers who have the flu.


The flu can lead to complications. The most common complications are:

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

For more vulnerable people, some complications can lead to hospitalization and even death.

People who have a higher risk of developing complications

People who have a higher risk of developing complications are:

  • Babies under 6 months of age
  • Children and adults who have chronic diseases
  • Pregnant women who have chronic diseases throughout their pregnancy
  • Healthy pregnant women in the 2nd and 3rd trimesters of their pregnancy
  • People age 75 and over

If you or your child has a higher risk of developing complications and you have flu symptoms, call Info-Santé 811. A nurse will assess your health and make recommendations based on your situation.


The flu virus prefers cool, dry places. It can live up to 2 days on contaminated objects and up to 5 minutes on skin.

The flu virus is very contagious. It spreads quickly from person to person:

  • By droplets expelled into the air from the mouth or nose of a person infected with the flu when they cough or sneeze
  • By direct contact with secretions from the nose or throat of a person infected with the flu, when kissing for instance
  • When you bring your hand to your nose, mouth or eyes after shaking the hand of a person who is infected or touching contaminated objects

A person infected with the flu virus may be contagious:

  • 24 hours before showing symptoms
  • Up to 7 days after the onset of symptoms and sometimes even a little longer. Young children and older adults may be contagious for up to 14 days after the onset of symptoms.

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

Protection and prevention

The best way to protect yourself from flu-related complications is by getting vaccinated.

Protection and hygiene measures can also help prevent the spread of the flu.

At all times

If you have the flu

Stay at home as soon as you develop flu symptoms. Unless advised otherwise by a doctor, home is the best place to recover. By staying at home, you limit contact with other people or with other infections that may cause complications. You also limit the spread of the virus.

Follow the recommendations for Coughing or Sneezing Without Contaminating

Last update: October 16, 2019


Information on the website in no way replaces the opinion of a health professional. If you have questions concerning your health status, consult a professional.


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