Influenza (Flu)

What is the flu?

The flu, or seasonal influenza, is a common contagious infection. The flu affects the nose, throat, and lungs. It is spread through droplets that have been coughed or sneezed by someone who has the flu. You can get the flu by shaking hands with someone who has the flu or by touching surfaces that have come into contact with flu droplets, and then touching your eyes, nose or mouth. Flu symptoms include a sudden fever or feeling feverish as well as a cough and/or a sore throat. It is common to also have a runny or stuffy nose, headache or body aches, and chills. You may feel more tired than usual and have a lower appetite. Some people (mostly children) also have nausea, vomiting, and/or diarrhea. Most people will recover within a week to 10 days, but some people are at greater risk of severe complications, such as pneumonia or death. Influenza infection can also worsen certain chronic conditions, such as heart disease. Although the burden of influenza can vary from year to year, it is estimated that there are an average of 12,200 hospitalizations related to influenza and approximately 3,500 deaths attributable to influenza annually in Canada.

Preventing the flu

You can help protect yourself against the flu by getting the flu vaccine. The earlier you get the vaccine, the better your chances are to prevent getting the flu virus. The flu is a viral infection that can have severe complications. Anyone can get the flu virus. The flu is not just a cold. You could miss school, work, parties, holidays, or even end up in the hospital.

The flu vaccine helps your body help itself. The vaccine will trigger your body to fight off infection if you come into contact with the flu. This means you either will not get the flu virus, or the symptoms will be greatly reduced. Each year, different strains of the flu virus appear. Scientists predict which strains will be most likely to affect us for the coming year. These strains are used to make up the year's flu vaccine. This is why it is important to be immunized with a flu vaccine each year, in the fall.

Getting your flu vaccine is good for everyone. When more people get their flu vaccine, the odds of the flu virus spreading goes down. This protects those who are most vulnerable such as children under five, adults 65 years or older, pregnant women, as well as those living with chronic health conditions like diabetes, cancer, and HIV/AIDS.

Along with getting your annual flu vaccine, you can help stop the spread of the flu, and protect yourself and your family by following a few easy steps:

• Wear a well-fitting mask to protect yourself and others in indoor or crowded spaces.
• Avoid touching your eyes, nose, mouth or mask with unwashed hands to prevent germs from entering your system
• Wash your hands often (or use hand sanitizer), especially after being in contact with others or being in a shared/public space
• Stay home when you’re sick – do not attend work, school or childcare or visit high-risk settings like long term care or retirement homes and hospitals. Make sure you wear a mask when you go out in public after feeling better until 10 days have passed.
• Choose to gather with people outside or in well-ventilated spaces where lots of space can be kept between people
• Cover your cough - cough or sneeze into your upper sleeve or into a tissue that you dispose of
• Clean and disinfect high touch surfaces regularly like doorknobs, light switches and railings
• Make a plan in the event you or your child/children have to stay home from work, school or daycare

Types of publicly funded vaccines

FluMist® Quadrivalent (AstraZeneca) is authorized for use but it is not publicly funded in this 2022-2023 flu season.

Children six months to under nine years of age who have never had a flu vaccine in their life require two doses of the flu vaccine, given at least four weeks apart. Children six months to less than nine years or anyone older who received one or more doses of seasonal flu vaccine in the previous year, should receive one dose of flu vaccine per season thereafter.

The standard-dose quadrivalent inactivated vaccine (QIV) continues to be a good option for individuals six months of age and over, including adults over the age of 65 years.

The QIV protects against four flu strains: two different flu A viruses and two different flu B viruses. TIV (Trivalent Inactivated Vaccine) protects against two different flu A viruses and one flu B virus. 

Fluzone® High-Dose Quadrivalent Inactivated Vaccine (QIV-HD) is also available for persons 65 years old and over. QIV-HD contains a higher amount of antigen per strain than standard-dose flu vaccine formulations. QIV-HD has a comparable safety and immunogenicity profile to the previously authorized TIV-HD. For individual-level decision making, NACI in Canada states that when available, high-dose should be used over standard-dose inactivated influenza vaccine, given the burden of influenza A(H3N2) disease and the good evidence of better protection compared to standard-dose in adults 65 years of age and older. However, NACI states that any of the available age-appropriate influenza vaccines should be used. There is no preferential recommendation for the use of QIV-HD versus TIV-adj vaccine for this age group. All QIV, QIV-HD, and TIV-adj vaccines protect people 65 years old and over against the flu and the most important thing is for older adults to be vaccinated.

Canadian Immunization Guide Chapter on Influenza and Statement on Seasonal Influenza Vaccine for 2022-2023

Vaccine precautions

It is important to screen yourself for symptoms before being vaccinated. Public health measures are in place at clinics to keep you and others safe. Please wear a mask, distance yourself from others and stay home if you are ill.

• The flu vaccine is safe for anyone 6 months of age or older who does not have a contraindication to the flu vaccine.
• The flu vaccine is safe and recommended during pregnancy and breastfeeding.
• Persons with egg allergy can safely receive any influenza vaccine and do not need any special precautions or testing.

You should not get the flu vaccine if you are:

• Feeling ill? You can get the flu vaccine when you are feeling better.
• Someone who has had a serious allergic reaction (anaphylaxis) to any of the components of that specific flu vaccine before (with the exception to egg). Consideration may be given to offering another flu vaccine that does not contain the implicated component.
• Someone who has had a serious allergic reaction (anaphylaxis) to a previous flu vaccine. A consultation with an allergist is recommended prior to flu vaccination
• Someone who has developed Guillain-Barré Syndrome (GBS) within 6 weeks of a previous flu vaccination, unless another cause was found for the GBS. You may be referred to a physician in this case.

You may also be referred to a physician if you have a history of severe Oculo-Respiratory Syndrome involving difficulty breathing or wheezing following receipt of seasonal flu vaccine.

Administration of flu vaccine with other vaccines

All seasonal influenza vaccines may be given at the same time as, or at any time before or after, administration of other routine vaccines, including the COVID-19 vaccine in individuals 6 months of age and older.

On December 9, 2022, NACI updated their guidance now recommending that COVID-19 vaccines may be given on the same day as or at any time before or after non-COVID-19 vaccines for children 6 months to 5 years of age.   

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