Patient Medication Information: uses, side effects, how to take - Influvac
What is INFLUVAC used for?
INFLUVAC is a vaccine used to prevent adults and children 6 months of age and older from developing influenza (the flu).
How does INFLUVAC work?
Like other influenza vaccines, INFLUVAC causes the body to produce antibodies against the virus. This means that when your body is exposed to the flu virus, your body is able to defend itself. The antibodies stop the attacking virus. You cannot catch influenza from INFLUVAC since it only contains portions of the virus, and not the whole live virus. Your body takes 10 to 21 days to produce antibodies after vaccination. Therefore, if you are exposed to influenza immediately before or after your vaccination, you could still develop the illness. The vaccine will not protect you against the common cold, even though some of the symptoms are similar to influenza. Influenza viruses change all the time, so different vaccines may be made every year. To stay protected against influenza, you need to be re-vaccinated every year before the winter season.
It is particularly important for some groups of people to be vaccinated. These include people with certain medical conditions, elderly people, people who are likely to be exposed to the infection and people on certain medications. If you are in doubt as to whether you should be vaccinated, talk to your local health care professionals.
What are the ingredients in INFLUVAC?
Medicinal ingredient: INFLUVAC complies with the World Health Organization (WHO) recommendations for vaccination in the northern hemisphere for the 2025/2026 season.
Each 0.5 mL pre-filled syringe for injection contains neuraminidase and 15 mcg haemagglutinin of the following virus strains:
- an A/Victoria/4897/2022 (H1N1) pdm09-like virus;
- an A/Croatia/10136RV/2023 (H3N2)-like virus; and
- a B/Austria/1359417/2021 (B/Victoria lineage)-like virus
Non-Medicinal Ingredients: Calcium chloride dihydrate, disodium phosphate dihydrate, magnesium chloride hexahydrate, potassium chloride, potassium dihydrogen phosphate, sodium chloride, water for injection and may also contain trace amounts of cetyltrimethyl ammonium bromide, chicken protein, egg material, formaldehyde, gentamicin sulphate (or neomycin sulphate, polymyxin B sulphate), hydrocortisone, polysorbate 80, sodium citrate, sucrose and tylosine tartrate.
INFLUVAC comes in the following dosage form:
A 0.5 mL pre-filled syringe.
Do not use INFLUVAC if:
- INFLUVAC vaccine is made in eggs; therefore this vaccine should not be given to anyone with allergies and especially severe allergies (anaphylactic reactions) to chicken eggs or egg products.
INFLUVAC should not be given to people who have allergies to the active substances, to any of the excipients and to residues of eggs, chicken protein, formaldehyde, cetyltrimethylammonium bromide, polysorbate 80, or gentamicin.
- For a complete listing of excipients, see DOSAGE FORMS, STRENGTHS, COMPOSITION AND PACKAGING section of the Product Monograph.
- Anyone who has experienced allergic reactions to a previous dose of influenza vaccine SHOULD NOT be vaccinated with INFLUVAC.
To help avoid side effects and ensure proper use, talk to your healthcare professional before you take INFLUVAC. Talk about any health conditions or problems you may have, including if:
- you have a fever, or you think you may be getting a fever
- you had a serious reaction to any flu vaccine in the past
- you have experienced any health problems
you are pregnant
- you are currently on any medication (i.e., immunosuppressants, theophylline, anticoagulants such as warfarin).
- You have experienced fainting, feeling faint or other stress related reactions with a previous injection.
Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.
How to take INFLUVAC:
INFLUVAC should only be given by a health care professional.
Usual Dose:
Adults: 0.5 mL, single dose.
children from 6 months of age: 0.5 mL. For children less than 9 years of age, who have not previously been vaccinated, a second dose should be given after an interval of at least 4 weeks.
The safety and efficacy of INFLUVAC have not been established in infants less than 6 months of age.
INFLUVAC comes as a 0.5 mL suspension, ready for intramuscular or deep subcutaneous injection. Allow the vaccine to reach room temperature (15-25°C) before use. Ensure that the product is returned to the refrigerator within 24 hours if not used.
Shake well before use.
Overdose:
Overdosage is unlikely to have any bad effect.
If you think you, or a person you are caring for, have taken too much INFLUVAC, contact a healthcare professional, hospital emergency department, or regional poison control centre immediately, even if there are no symptoms.
What are possible side effects from using INFLUVAC?
These are not all the possible side effects you may have when taking INFLUVAC. If you experience any side effects not listed here, tell your healthcare professional.
Occasionally people have side effects with influenza vaccines. The most common of these are fever, feeling unwell, irritability (in children 6 months of age to 5 years old), shivering, tiredness, headache, sweating, muscle or joint pain, and warmth. Skin reactions include redness, swelling, pain, ecchymosis (blue/black staining of the skin), a hardening of the skin at the injection site and itching.
These reactions will normally disappear without treatment in 1-3 days.
Rarely, neuralgia (nerve pain), paresthesia (numbness and tingling), convulsions (seizures) and temporary thrombocytopenia (a blood disorder) have been reported. In rare cases, allergic reactions may lead to shock.
Very rarely, vasculitis (inflammation of blood vessels) temporarily affecting the kidneys, neurological disorders (affecting the nerves and brain) such as encephalomyelitis, neuritis and Guillain Barré syndrome have been reported.
Allergic reactions (this might include but is not limited to breathing or swallowing difficulties, or swelling in the face or skin), and temporary enlargement of the lymph nodes have been reported.
Serious side effects and what to do about them
| Symptom / effect | Talk with your healthcare professional | Stop taking drug and get immediate medical help | |
| Only if severe | In all cases | ||
| Common | |||
| fever | X | ||
| feeling unwell | X | ||
| shivering | X | ||
| tiredness | X | ||
| headache | X | ||
| sweating | X | ||
| muscle or joint pain | X | ||
| Skin Reactions | |||
| redness | X | ||
| swelling | X | ||
| pain | X | ||
| ecchymosis (blue/black staining of the skin) | X | ||
| reddening of the skin at the injection site | X | ||
| Uncommon | |||
| nerve pain | X | ||
| numbness and tingling | X | ||
| convulsions (seizures) | X | ||
| temporary thrombocytopenia (a blood disorder) | X | ||
| allergic reactions | X | ||
| inflammation of blood vessels temporarily affecting the kidneys | X | ||
| brain disorders | X | ||
| Guillain Barré syndrome | X | ||
If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.
Reporting Suspected Side Effects for Vaccines
For the general public: Should you experience a side effect following immunization, please report it to your healthcare professional.
Should you require information related to the management of the side effect, please contact your healthcare professional. The Public Health Agency of Canada, Health Canada and BGP Pharma ULC cannot provide medical advice.
For healthcare professionals: If a patient experiences a side effect following immunization, please complete the Adverse Events Following Immunization (AEFI) Form appropriate for your province/territory (http://www.phac-aspc.gc.ca/im/aefi-essi-form-eng.php) and send it to your local Health Unit.
Storage:
Store INFLUVAC at 2 to 8°C (in a refrigerator).
Do not freeze. Store in the original package in order to protect from light.
Do not use after the expiry date.
This vaccine is effective against this year’s 2025/2026 influenza virus.
Keep out of reach and sight of children.
If you want more information about INFLUVAC:
- Talk to your healthcare professional.
- Find the full product monograph that is prepared for healthcare professionals and includes this Patient Medication Information by visiting the Health Canada website: (https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/drug-product-database.html; the manufacturer’s website www.viatris.ca, or by calling 1-844-596-9526.
- This information is current up to the time of the last revision date shown below, but more current information may be available from the manufacturer.
® Registered Trademark of BGP Products B.V., licensed use by BGP Pharma ULC, a Viatris company