Flu (influenza): Symptoms and treatment

The flu is a contagious viral respiratory disease.

Symptoms of the flu

Flu symptoms may vary from person to person. Some people get mildly ill. Others get very sick.

Flu symptoms generally appear 1 to 4 days after exposure to the virus. Symptoms usually include the sudden appearance of:

fever
cough
muscle aches and pain

Other common symptoms may include:

chills
tiredness
headache
sore throat
loss of appetite
runny or stuffy nose

Some people (especially children) may also have:

diarrhea
nausea and vomiting

You are contagious from the day before your first symptoms until about 5 days after your first symptoms. Children and people with weakened immune systems may be contagious for longer.

Other symptoms to watch for in children

As a parent, you know your child best. Talk to a health care provider right away if your child is:

not waking up or interacting with others
having difficulty breathing
not drinking or eating as usual
not wanting to play or be held (irritable)

Complications of flu

Possible serious complications and outcomes of the flu include:

worsening of chronic health conditions
heart complications
pneumonia and respiratory failure
hospitalization
death

If you become ill

If you do get sick, stay home to prevent spreading the flu. Avoid close contact with other people until you no longer have symptoms. It's especially important to protect those who have a higher chance of developing complications from the flu. You can also use personal protective measures to help keep others safe, like:

wearing a well-fitting mask
cleaning your hands regularly
covering your coughs and sneezes

Most people recover from the flu in 7 to 10 days.

If you're at higher risk and you develop symptoms, contact a health care provider for advice.

Before an in-person appointment, tell the health care provider about your symptoms over the phone and follow their instructions.

If you need immediate medical attention, call 911 and tell them your symptoms.

Learn more:

Diagnosing the flu

It can be hard to tell the difference between symptoms of the flu and other respiratory illnesses like COVID-19.

Your health care provider can diagnose the flu based on your:

symptoms
laboratory tests (nose or throat swab)

Treating the flu

Flu symptoms can improve with:

rest
fluids, like water
over-the-counter medication to reduce fever or aches

In some cases, a health care provider may prescribe specific medication against the flu (for example, antivirals), especially if you're:

very sick with severe symptoms
at higher risk for complications

Over-the-counter cough and flu medicine should not be given to children younger than 6 years old. It's only safe to do so if your health care provider advises it.

Consider becoming a FluWatcher

FluWatchers is a volunteer program that helps track the activity of common viruses like flu, respiratory syncytial virus (RSV) and COVID-19 in Canada.

Once you sign up, you'll receive an email once a week asking if you had a cough or fever in the previous week. This serves as an early warning sign for respiratory illness activity, which helps public health officials predict and respond to potential outbreaks.

It only takes about 15 seconds to complete through our secure portal and your answers are anonymous.

Become a FluWatcher

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Date modified:: 2024-10-07

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