Influenza vaccine information for health professionals

Key Messages

  • Immunization is the most effective strategy to prevent and reduce the impact of influenza in our community.
  • The influenza vaccine is an extremely important layer of protection against the flu, especially for high risk groups, and has been shown to reduce influenza-related complications, hospitalizations, and deaths.
  • For your convenience, Ottawa Public Health offers influenza related information and resources to support your practice, including information for your patients.
Influenza strains covered by the vaccine

The 2023-2024 seasonal influenza vaccines protect against the following influenza strains:
Quadrivalent vaccines:
Egg-Based Vaccines (Fluzone® Quadrivalent, FluLaval® Tetra, and Fluzone® High-Dose Quadrivalent):

  • A/Victoria/4897/2022 (H1N1)pdm09-like virus; A/Darwin/9/2021(H3N2)-like virus
  • B/Austria/1359417/2021(B/Victoria lineage)-like virus; and
  • B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.

Egg-Based Trivalent vaccine (Fluad®):

  • A/Victoria/4897/2022 (H1N1)pdm09-like virus;
  • A/Darwin/9/2021(H3N2)-like virus; and
  • B/Austria/1359417/2021(B/Victoria lineage)-like virus
Populations recommended to be immunized and schedule

Per the National Advisory Committee on Immunization (NACI) recommendations for influenza and to optimize co-administration with COVID-19 vaccine, health care workers, first responders, and the following individuals at high risk of influenza-related complications or who are more likely to require hospitalization, should be prioritized to receive the influenza vaccine as soon as vaccine is available:

  • Residents and staff of congregate living settings (e.g. chronic care facilities, retirement homes)
  • People > 65 years of age
  • All pregnant individuals
  • All children 6 months to 4 years of age
  • Individuals who are from a First Nation, Inuit or Métis community, and/or who self-identify as First Nation, Inuit or Métis, and their household members
  • Members of racialized and other equity deserving communities
  • Individuals 6 months of age and older with the following underlying health conditions:
    • Cardiac or pulmonary disorders
    • Diabetes mellitus or other metabolic disease
    • Cancer
    • Conditions or medication which compromise the immune system
    • Renal disease
    • Anemia or hemoglobinopathy
    • Neurologic or neurodevelopment conditions
    • Morbid obesity (body mass index of >40)
    • Children and adolescents (6 months to 18 years) undergoing treatment with acetylsalicylic acid for long periods

The influenza vaccine is recommended for all people six months of age and older without contraindications, however, per NACI, individuals in the following three groups are particularly recommended to receive the influenza vaccine and should receive the vaccine starting October 30, 2023:

  1. Individuals capable of transmitting influenza to those listed in the high-risk group above and/or to infants under 6 months of age:
  • Health care workers and other care providers in facilities and community settings
  • Household contacts (adults and children) of individuals at high risk of influenza related complications
  • Persons who provide care to children < 4 years of age
  • Members of a household expecting a newborn during the influenza season
  • Those who provide services within a closed or relatively closed setting to persons at high risk of influenza related complications (e.g. crew on a ship)
  • Although seasonal influenza vaccination will not prevent avian influenza infection, NACI recommends seasonal influenza vaccination for poultry workers, based on the rationale that preventing infection with human influenza strains may reduce the theoretical potential for human-avian reassortment of genes, should such workers become co-infected with human and avian influenza viruses.
  1. People who provide essential community services
  2. Poultry industry workers

How many vaccine doses are required?

Two doses are recommended for children six months to under nine years of age receiving seasonal influenza vaccine for the first time in their life, with a minimum interval of four weeks between doses. All others require only one dose annually.

Contraindications to influenza immunization

Influenza vaccine is contraindicated in:

  • Persons who have developed Guillain-Barré Syndrome (GBS) within six weeks of influenza vaccination, unless another cause was found for the GBS.
  • Persons who have developed an anaphylactic reaction to a previous dose of influenza vaccine or to any of the vaccine’s components, except for egg.
    • Egg-allergic individuals may be vaccinated against influenza without prior influenza vaccine skin test and with the full dose, irrespective of a past severe reaction to egg, and without any extraordinary precautions, but ensuring that, as with all vaccine administration, immunizers be prepared with the necessary equipment, knowledge and skills to respond to a vaccine emergency always.
    • In situations of suspected hypersensitivity or non-anaphylactic allergy to a vaccine or its components, investigation is indicated which may involve immunization in a controlled setting. Consultation with an allergist is advised. If an individual is found to have an anaphylactic reaction to a component in one influenza vaccine, consideration may be given to offering another influenza vaccine that does not contain the implicated component, in consultation with an allergy expert. Individuals who have an allergy to substances that are not components of the influenza vaccine are not at increased risk of allergy to influenza vaccine

For more information, please consult the product monographs:

Vaccine products publicly funded in Ontario

Influenza vaccine is recommended for everyone six months of age and older who does not have contraindications to the vaccine.

Detailed product recommendations from NACI are available at: 

Canadian Immunization Guide Chapter on Influenza and Statement on Seasonal Influenza Vaccine for 2023-2024


Age indication

Influenza Vaccine Formulation

Dosage and Route of Administration


Most common allergens

FluLaval® Tetra

six months of age and older

Quadrivalent Inactivated Vaccine (QIV or IIV4-SD)

0.5mL IM

  • Multi-dose vial (MDV)
  • Egg Protein*
  • Thimerosal

Fluzone® Quadrivalent

six months of age and older

Quadrivalent Inactivated Vaccine (QIV or IIV4-SD)

0.5mL IM

  • Multi-dose vial (MDV)
  • Pre-filled Syringes (PFS)
  • Egg Protein*
  • Thimerosal** (multi-dose vial only)

Fluzone® High-Dose Quadrivalent

65 years of age and older

High-Dose Quadrivalent Inactivated Vaccine (QIV-HD or IIV4-HD)

0.7mL IM

  • Pre-filled Syringes (PFS)
  • Egg Protein*


65 years of age and older

Adjuvanted Trivalent Inactivated Vaccine (TIV-adj or IIV3-Adj)

0.5mL IM

  • Pre-filled Syringes (PFS)
  • Egg protein*
  • Kanamycin
  • Neomycin

* Egg allergy is not a contraindication to receiving the influenza vaccine

**Thimerosal-free QIVs in pre-filled syringe format Fluzone® Quadrivalent are available for those with a thimerosal allergy. 

Important notes:

  • Fluzone® Quadrivalent and Fluzone® High-Dose Quadrivalent are different products. Fluzone® High-Dose Quadrivalent is only authorized for those 65 years of age and older. Please use caution when administering Fluzone® products to ensure that the right vaccine is being administered to the right person.

Choosing between QIV standard dose (SD), QIV High Dose (HD) and TIV-Adj for patients 65 years of age and older:

Rather than delay vaccination for a particular product, the recommendation is to vaccinate older adults with either the QIV, QIV-HD or TIV-adj which all protect against the flu.

For individual-level decision making, NACI in Canada states that when available, high-dose is recommended 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 can be used. There is no preferential recommendation for the use of QIV-HD versus TIV-adj vaccine for this age group.

To date, no studies have directly compared QIV-HD and TIV-adj formulations or TIV-adj and QIV formulations.

Please consider the following information when discussing vaccine options:

  • There is insufficient evidence to make a preferential recommendation between QIV-HD and TIV-adj. There is good evidence of QIV-HD providing better protection compared to QIV standard dose.
  • In considering use of TIV-adj and QIV standard dose, given the increased burden of disease associated with influenza A(H3N2) in older adults, better protection against influenza A(H3N2) afforded by the TIV-adj may be more important, especially in those with multiple co-morbid conditions and compromised health status.

For more information on high-dose QIV, TIV-Adj and QIV, please refer to the Canadian Immunization Guide Chapter on Influenza and Statement on Seasonal Influenza Vaccine for 2023-2024.

More information for individuals 65 years of age and older can be found here Health Care Providers Q&A for individuals 65 years of age and older.


Vaccine ordering and pick up

Vaccine Distribution Centre hours are Monday to Friday, 8 am to 4 pm.

NOTE: On all Statutory holidays The Vaccine Distribution Centre is closed.

  1. To order vaccine, please use the Influenza Vaccine Order Form 2023/2024 from Ottawa Public Health to order vaccine (not the Ministry of Health form).
  2. Place your order by completing the number of doses required on the form. Orders will be filled in the order in which they are received, with priority to high-risk groups. The first auto-shipment will contain a predetermined amount of vaccine to be shipped to vaccinate high-risk patients. Additional influenza orders can be placed on or after October 10. Please allow up to seven business days for your order to be processed.
  3. OPH recommends reserving some vaccine for persons age 65 years and older, and persons under 65 with medical conditions that put them at high risk for influenza-related complications.
  4. Your clinic/facility will be called when your order is ready. Please arrange to pick up your order within 48 hours of notification at the Ottawa Public Health Vaccine Distribution Centre, on the ground floor of 100 Constellation Drive.
  5. You will need to bring your own cooler and two ice packs per cooler.
Vaccine that is not used by your clinic/facility cannot be redistributed. To reduce vaccine wastage, please only order the quantity that you are sure to use within the month. You can order more vaccine as needed. Unused vaccine can be returned to the Ottawa Public Health Immunization Program once you are finished immunizing for the season using Ottawa Public Health Vaccine Return Form
Report of adverse events following immunization (AEFI)

All adverse events following administration of an influenza vaccine must be reported to Ottawa Public Health within 24 hours by fax to 613-580-9660 using the AEFI reporting form.

Find more information about what constitutes an AEFI, please see Public Health Ontario's Fact Sheet on AEFI Reporting for Health Care Providers or Public Health Ontario's webpage on Vaccine Safety. If you have any questions related to the reporting of adverse events following immunization, please call 613-580-6744 and select “1” for English then “2” for healthcare provider; your call will be prioritized for answer by the next available public health nurse.

Health care agencies and workplaces providing influenza vaccine clinics

Ottawa Public Health seeks to support you in your efforts to increase influenza vaccine uptake in your facility or workplace by offering information and resources.

In you cannot find the information you seek here, please call 613-580-6744 and select “1” for English then “2” for healthcare provider; your call will be prioritized for answer by the next available public health nurse.

Information from the Ministry of Health on the 2023/2024 Universal Influenza Immunization Program (UIIP)  is also available.

Return unused vaccine to the Ottawa Public Health Immunization Program once you are finished immunizing for the season using Ottawa Public Health Vaccine Return Form.

Additional Resources

Contact Us

For questions regarding a vaccine order email or call 613-580-6744 and follow prompts for the Vaccine Distribution Centre.

To have your call prioritized as a health care provider, please call 613-580-6744 and select “1” for English then “2” for healthcare provider; and your call will be prioritized for answer by the next available public health nurse.

Contact Us