Influenza Information for Health Professionals

This site area is currently being updated to align with guidance for the upcoming 2024-2025 respiratory illness season.

 

Influenza virus, also known as the flu, is caused by influenza A and B viruses. Each year in Canada, about five to ten percent of adults and 20 to 30 percent of children are infected with influenza, usually in the late fall and winter months. The flu can cause serious complications among young children, older adults, pregnant people, people with chronic medical conditions, Indigenous people, and residents of long-term care homes and others chronic care facilities. Symptoms can be difficult to distinguish from other common respiratory illnesses.

For more information on clinical signs and symptoms, surveillance, laboratory testing, IPAC, reporting and patient resources, please see Respiratory Viruses Information for Health Professionals.

This year, the ministry of health is recommending co-administration of COVID-19 and influenza vaccines.

Publicly Funded Influenza Vaccines for the 2023/2024 Flu Season

Table 1. Publicly funded influenza vaccine available through the 2023/2024 UIIP for individuals 6 months of age and older

Quadrivalent Inactivated Vaccine
UIPP Abbreviation QIV –
NACI Abbreviation IIV4-SD –
Vaccine product FluLaval Tetra Fluzone® Quadrivalent
Manufacturer GSK Sanofi Pasteur
Age indication ≥6 months ≥6 months
Vaccine type Egg-based Egg-based
Micrograms of hemagglutinin 15 µg 15 µg
Dosage 0.5 mL 0.5 mL
Format MDV
  1. MDV
  2. PFS
Route IM IM
Most common allergens1
  • Egg protein2
  • Thimerosal3
  • Egg protein2
  • Thimerosal3
Post-puncture shelf life 28 days4 MDV: 28 days4
PFS: Not applicable
Product dimensions (cm) 2.7 x 6.9 x 2.7 MDV: 5.8 x 5.4 x 3.6
PFS: 10.4 x 9.9 x 3.8
  1. Any component in a vaccine may be a potential allergen. This table identifies the most common allergens.
  2. The National Advisory Committee on Immunization (NACI) indicates that egg allergy is not a contraindication for influenza vaccination and that egg-allergic individuals may be vaccinated against influenza using the full dose of any age-appropriate product.
  3. Multi-dose vial format only
  4. Report all vaccine wastage and return only unopened vials/syringes/ampoules to PHU or OGPMSS (for Toronto clients) as wastage. Discard opened vials/syringes/ampoules through biohazard waste.

Table 2. Publicly funded influenza vaccine available through the 2023/2024 UIIP for individuals 65 years of age and older

Note: Fluzone® QIV-HD, Fluad® TIV-adj are approved just for seniors to give better protection against the flu. Both vaccines may cause more soreness, redness and swelling where the vaccine was given, lasting a few days longer than the standard flu vaccine.

The most important thing is for older adults to be vaccinated.  DO NOT delay vaccination to wait for a particular vaccine product.

High-Dose Quadrivalent Inactivated Vaccine Adjuvanted Trivalent Inactivated Vaccine
UIPP Abbreviation QIV-HD TIV-adj
NACI Abbreviation IIV4-HD IIV3-Adj
Vaccine product Fluzone® High-Dose Quadrivalent Fluad®
Manufacturer Sanofi Pasteur Seqirus
Age indication ≥65 years ≥65 years
Vaccine type Egg-based Egg-based
Micrograms of hemagglutinin 60 µg 15 µg
Dosage 0.7 mL 0.5 mL
Adjuvant No Yes
Format PFS PFS
Route IM IM
Most common allergens1
  • Egg protein2
  • Egg protein2
  • Kanamycin
  • Neomycin
Post-puncture shelf life Not applicable Not applicable
Product dimensions (cm) 10.4 x 9.9 x 2.3 12.7 x 6.35 x 9.4
  1. Any component in a vaccine may be a potential allergen. This table identifies the most common allergens.
  2. The National Advisory Committee on Immunization (NACI) indicates that egg allergy is not a contraindication for influenza vaccination and that egg-allergic individuals may be vaccinated against influenza using the full dose of any age-appropriate product.

2023/2024 Vaccine Re-Ordering

The deadline to apply to order vaccine for the 2023/2024 season has passed.

Organizations interested in becoming a vaccine provider for the Universal Influenza Immunization Program (UIIP) are required to complete an annual application process for approval to store, handle, and administer publicly funded influenza vaccine unless they are in receipt of other publicly funded vaccines (excluding COVID-19 vaccine).

Homebound Vaccination Referrals

Your patient may be eligible for homebound vaccination if they have medical, cognitive, or psychosocial needs/conditions that inhibit them from visiting you, their primary care provider, or a pharmacist to receive an influenza or COVID-19 vaccine. Transportation and other strategies to remedy the access difficulties should have also been considered but are not available or not appropriate in your patient’s circumstances.

Primary care providers:

  • Identify patients who qualify
  • Get consent for homebound vaccination
  • Refer eligible individuals using the updated template

Note: Primary care providers must register eligible patients this year even if the patient previously received a homebound influenza or COVID-19 vaccination. Registered patients will be screened again by Toronto Paramedic Services during the booking process.

More information:

The Chief Medical Officer of Health requests that health care providers maintain a heightened index of suspicion for patients with severe influenza as part of enhanced surveillance for avian influenza, including:

  • Obtain a history from individuals with severe influenza regarding potential exposures to infected birds or mammals, or to contaminated surfaces, in the past 14 days prior to illness onset.
  • For patients with influenza and a relevant potential exposure, influenza A samples (non-H3/non-H1 samples, in known) should be forwarded to PHOL for sub-typing. Contact PHO Laboratory Customer Service Centre at 1-877-604-4567 prior to submitting specimens.

More information about avian influenza: