Influenza (Flu)

Influenza (also known as the flu) is a contagious infection of the nose, throat and lungs. It is caused by the influenza A and B viruses and while certain people are more at risk, it can cause mild to severe illness in people of all ages.

Signs and Symptoms

How does the flu spread?

Who is most at risk?

How can I protect myself?

Flu Vaccine

Cold vs. Flu

Healthcare providers

Resources

Signs and Symptoms

• fever
• cough
• headache 
• muscle aches
• chills
• loss of appetite
• tiredness
• sore throat
• nausea, vomiting and diarrhea (especially in children)

How does the flu spread?

The flu spreads easily from person to person through droplets from coughing, sneezing, or talking. These droplets can land on the mouths, noses, or eyes of people nearby.

You can also catch the flu by touching unwashed hands or contaminated surfaces like toys, doorknobs, or utensils, and then touching your face.

It can take 1 to 7 days to show flu symptoms after being infected. People can spread the flu before they feel sick.

Most people with the flu recover from the flu in 7 to 10 days, but some are at higher risk of serious complications like pneumonia or worsening of existing health conditions.

Who is most at risk?

Getting your flu vaccine is the best way to protect yourself from the most severe outcomes of infection, including hospitalization caused by the flu. Most people with the flu recover from the flu in 7 to 10 days, but some are at higher risk of serious complications like pneumonia or worsening of existing health conditions.
Everyone aged 6 months of age and older who lives, works or goes to school in Ontario may receive a flu vaccine

Most people with the flu recover from the flu in 7 to 10 days, but some are at higher risk of serious complications like pneumonia or worsening of existing health conditions.

High-risk and priority populations

The following individuals are at a higher risk of influenza-related complications or are more likely to require hospitalization and should receive the vaccine as soon as it becomes available:

• populations at high-risk of infection
• staff and care providers in congregate living settings (such as chronic care facilities, long-term care homes, retirement homes)
• health care workers
• first responders
• members of underserved communities
• people whose occupational or recreational activities increase their risk of exposure to avian influenza A viruses
• people with significant exposure to birds or mammals are more likely to have significant exposure to influenza A(H5N1) (such as poultry, livestock, slaughterhouse and processing plant workers, wildlife officers/researchers, and veterinarians)
• Seasonal influenza vaccines do not provide protection against infection with influenza A(H5N1) viruses. However, they may reduce the risk of seasonal human and influenza A(H5N1) virus co-infection and possible viral reassortment leading to a human-transmissible virus with pandemic potential.

When vaccine becomes available to the public at the end of October, it is recommended that the following groups receive their flu vaccine to help protect themselves and others at risk:

• people who provide essential community services
• people who might spread the flu to high-risk populations and/or to infants
• care providers in the community
• household contacts (adults and children) of people at high risk of influenza related complications
• people who provide care to children 4 years of age or younger
• members of a household expecting a newborn during the influenza season
• those who provide services within a closed or relatively closed setting to people at high risk of influenza related complications (such as ship crews)

If you live, work, or visit high-risk individuals often, getting the flu shot is strongly recommended to protect both yourself and them.

How can I protect myself from the flu?

1. Get the flu vaccine

The flu vaccine is your best defense against getting the virus and spreading it to others. The vaccine is recommended for everyone 6 months of age and older.

2. Wash your hands

Clean your hands frequently with soap and water or alcohol-based hand sanitizers. Hands should be cleaned after handling tissues, blowing your nose, shaking hands, touching objects around you and before preparing and eating food.

3. Stay home if you feel sick

Employees should check with their employer for return to work procedures and parents should check with their child's school/child care centre. 

4. Cover your cough or sneeze

Cough or sneeze into a tissue and throw it away. If you don’t have a tissue, cough or sneeze into your sleeve. Always clean your hands after coughing or sneezing.

5. Keep your distance

Avoid shaking hands and close contact with people who are sick. 

Flu Vaccine

Getting the flu vaccine is the best way to protect yourself against the most severe outcomes of the infection.

• Who should get the flu vaccine?
• Which flu vaccine should you get?
• Where can you get the flu vaccine?
• Where can you find more information on the flu vaccine? 

 Who should get the flu vaccine?

 The flu vaccine is recommended for everyone 6 months of age and older.

• The vaccine is safe, even for children and pregnancy individuals
• The vaccine is free even if you don't have an Ontario Health Card
• It is important to get the flu vaccine each year because the vaccine is updated based trends and the latest evidence.
• Children 6 months to under 9 years of age who have never received a dose of flu vaccine are recommended to have two doses at least 4 weeks apart. All other individuals require one dose each fall.

Which flu vaccine should you get?

The following flu vaccines are available for the 2025-2026 flu season. Supply of certain vaccine products may fluctuate during the season.

• 6 months to 64 years old:
• Trivalent Inactivated Vaccine (Fluviral, Fluzone, Flucelvax)
• 65 years of age and older:
• High-Dose Trivalent Inactivated Vaccine (Fluzone High-Dose)
• Adjuvanted Trivalent Inactivated Vaccine (Fluad)
• Trivalent Inactivated Vaccine (Fluviral, Fluzone, Flucelvax)

For adults 65 years and older, the high-dose and adjuvanted flu vaccines provide the best protection. High-dose vaccine has more antigen to help create a stronger immune response and adjuvanted vaccine, contains an adjuvant that boosts the body’s response to the vaccine.
However, it is not recommended to delay vaccination while waiting for a specific type.
All flu vaccines are safe and effective for seniors.

Where can you get the flu vaccine?

The following options are available to get the flu vaccine. Call ahead to the location to make sure the flu vaccine is available and see if an appointment is needed.

• Doctor or nurse practitioner clinic
• Pharmacy
• Pharmacies can provide flu vaccine to all individuals 2 years of age and older, including individuals without an Ontario Health Card (OHIP).
• Families with children 4 years of age and under can call the Health Unit at 519-663-5317 to discuss other options.
• The flu vaccine can be given at the same time, or before / after any other vaccines.

Where can you get more information on the flu vaccine?

• Ministry of Health (Ontario)
• The flu
• Flu vaccine for kids and during pregnancy
• Public Health Agency of Canada - Flu (Influenza): Get your flu shot
• Call the Health Unit to speak with a Public Health Nurse on our Vaccine Preventable Disease Team at 519-663-5317

What is the difference between a cold and the flu?

Symptoms of the common cold and the flu are often very similar. However, colds do not generally result in serious health problems such as pneumonia or bacterial infections.

Please note: Children may also experience croup, ear infections, nausea, vomiting and diarrhea when they have the flu. These symptoms are not common in adults.