Influenza vaccination Q&A

There are a lot of questions and misconceptions about the flu. Take a look at the flu Q&A below and get the facts. The more you know, the better prepared you’ll be to get your flu shot this year.

    If you don’t have symptoms, you can still spread the flu.

    Although you may not have symptoms for a number of days after being exposed to the virus, you can still be contagious. That’s why it’s good to practice healthy habits all year round, like washing your hands often and covering your nose and mouth when you sneeze or cough.

    Yes, you should get a flu shot every year.

    Because flu viruses change year to year, so do the vaccines. In order to keep up with the changing viruses, you need to be vaccinated with the current vaccine every single year.

    Influenza (flu) vaccines (often called “flu shots”) are vaccines that help protect against strains of the influenza virus that scientists at the World Health Organization (WHO) anticipate to be the most representative virus types in circulation.

    Vaccines contain very small amounts of specific ingredients, all of which play necessary roles either in making the vaccine, or in ensuring that the vaccine is safe and effective.


    Thimerosal is a preservative used in multi-dose vials of the flu vaccine to keep them free from contamination and contains an organic form of mercury called ethyl mercury.

    There is no evidence of harm caused by the low doses of thimerosal in vaccines.

    Flu vaccines available as single-dose, pre-filled syringes do not contain thimerosal.


    Formaldehyde occurs naturally in the human body and helps us digest food.

    It is used to inactivate viruses and bacteria that might contaminate the vaccine during production. Almost all of the formaldehyde is removed before the vaccine is packaged. There is approximately 10 times more formaldehyde in a baby’s body at any time than there is in a flu vaccine.


    All free flu vaccines provided by Ontario are aluminum-free. Aluminum is used in some other types of vaccines to enhance the immune system’s response after immunization.

    You shouldn’t wait until peak flu season to get vaccinated.

    Flu vaccinations are designed to last all season long. So, it's best to get yours as soon as the vaccine is available. Plus, it takes about 2 weeks for antibodies to develop to help protect against the flu, so you shouldn't wait until peak flu season.

    Getting vaccinated twice as an adult won’t give you double the protection.

    For adults, there is no evidence suggesting that more than one annual dose of the flu vaccine provides any additional protection.

    Sometimes children require a different dosing schedule of the flu vaccine to help prime their immune systems, but they’re not getting double vaccinated

    You should get your flu shot annually, as soon as the flu vaccine is available in the early fall. If you don’t have a chance to get a flu shot right away, vaccination throughout flu season into the winter months and beyond is still recommended and beneficial.

    The flu shot works by introducing your body to tiny little parts of different flu viruses. This triggers a reaction from your immune system — the processes in your body that fight off infection. Your immune system realizes these virus fragments shouldn't be in your body, and figures out how to destroy them.

    Influenza vaccines are now widely available at pharmacies, workplace flu clinics, retirement homes, and many more places.

    You should get vaccinated at the place that is most convenient for you.

    Check our clinic locator to find the nearest location to you.