2025–2026 Training Bulletin: Influenza Educational Review

Document purpose

This training bulletin provides paramedics information on NACI's Canadian Immunization Guide Chapter on Influenza and Statement on SeaThis training bulletin provides paramedics information on National Advisory Committee on Immunization's (NACI's) Canadian Immunization Guide Chapter on Influenza and Statement on Seasonal Influenza Vaccine for 2025/2026, as well as additional considerations for paramedics.

The National Advisory Committee on Immunization (NACI) Statement on seasonal influenza vaccine for 2025/2026 is available on the Government of Canada’s website.

Key information

The following are the key information points, taken directly from NACI statement for the 2025/2026 influenza season:

What

• Influenza in humans is a respiratory infection caused primarily by influenza A and B viruses. Seasonal influenza epidemics occur annually in Canada, generally in the late fall and winter months. Each year, there are approximately 3 to 5 million cases of severe influenza illness and 290,000 to 650,000 deaths from influenza worldwide.
• Most people will recover from influenza within 7 to 10 days, but some people are at greater risk of severe complications, such as pneumonia. Influenza infection can also worsen certain chronic conditions, such as cardiovascular disease.
• Inactivated influenza vaccines (IIV) (which include standard dose [SD], high dose [HD], cell culture-based [cc] or adjuvanted [Adj] vaccines), recombinant influenza vaccine (RIV) and live attenuated influenza vaccine (LAIV) are all authorized for use in Canada.
• Influenza vaccines are the best protection against influenza, and their benefits outweigh the potential risks following immunization. The safety profile of influenza vaccines has been well established. Reactions following immunization are generally benign and of short duration. In rare cases, individuals may have an allergic reaction to a component of the vaccines currently in use. Monitoring of safety signals related to influenza vaccines is ongoing.

Who

• NACI recommends that influenza vaccine should be offered annually to anyone 6 months of age and older who does not have a contraindication to the vaccine. Patients and providers should also be aware that risks of acquiring influenza are higher in some settings and risks from influenza infection are higher in some individuals than others. Immunization is particularly important for the following groups:
  • People at high risk of severe disease, influenza-related complications, or hospitalization.
  • People capable of transmitting influenza to those at high risk.
  • People who provide essential community services (including health care workers); and
• People whose occupational or recreational activities increase their risk of exposure to avian influenza A viruses (for example, H5N1).

The national goal of the annual influenza immunization programs in Canada is to prevent serious illness caused by influenza and its complications, including death. Programmatic decisions to provide influenza vaccination to all eligible or target populations as part of publicly funded provincial and territorial programs depend on many factors, such as cost-effectiveness evaluation and other programmatic and operational factors.

• NACI recommends that influenza vaccine should be offered as a priority to the groups for whom influenza vaccination is particularly important.

How

The benefits and risks of influenza vaccination should be discussed prior to vaccination, including the risks of not being immunized.

Choice of influenza vaccine

A variety of influenza vaccines are authorized for use in Canada, some of which are authorized for use only in specific age groups. Furthermore, not all products are available in all jurisdictions and availability of some products as part of publicly funded provincial and territorial programs may be limited or variable year to year.

Dose and route of administration

The dose and route of administration vary by influenza vaccine product.

See Appendix B for information on characteristics of all influenza vaccines expected to be available for use in Canada for the 2025–2026 influenza season. As the global transition to trivalent influenza vaccines continues, the availability of various influenza vaccine preparations in Canada is evolving. If the availability of a specific vaccine change (that is, be made available or unavailable) after the release of this statement and prior to the 2025-2026 influenza vaccine season, NACI will communicate relevant information regarding the new vaccine preparations if required.

Schedule

NACI recommends that:

• Adults and children 9 years of age and older should receive 1 dose of influenza vaccine each year; and
• Children 6 months to less than 9 years of age who have never received the seasonal influenza vaccine in a previous influenza season should be given 2 doses of influenza vaccine in the current season, with a minimum interval of 4 weeks between doses. Children 6 months to less than 9 years of age who have been vaccinated with 1 or more doses of seasonal influenza vaccine in any previous season should receive 1 dose of influenza vaccine per season thereafter.

Contraindications

For all influenza vaccines (IIV, RIV and LAIV), NACI recommends that influenza vaccination should not be given to:

• People who have had an anaphylactic reaction to a specific influenza vaccine, or to any of the components of a specific influenza vaccine, with the exception of egg.
• If an individual is found to have an anaphylactic reaction to a component in 1 influenza vaccine, consideration may be given to offering another influenza vaccine that does not contain the implicated component, in consultation with an allergy specialist.

For LAIV, in addition to the above-mentioned contraindication, NACI also recommends that LAIV is contraindicated for:

• People with severe asthma (defined as currently on oral or high dose inhaled glucocorticosteroids), active wheezing, or medically attended wheezing in the 7 days prior to the proposed date of vaccination, due to increased risk of wheezing following administration of LAIV;
  • LAIV is not contraindicated for people with a history of stable asthma or recurrent wheeze which is not active.
• Children less than 24 months of age, due to increased risk of wheezing following administration of LAIV.
• Children 2 to 17 years of age currently receiving long-term aspirin or aspirin-containing therapy, because of the association of Reye's syndrome with aspirin and wild-type influenza infection.
• Pregnant women and pregnant individuals, because it is a live attenuated vaccine and there are limited data on safety and effectiveness of LAIV in this population. There has been no identified safety signal regarding the use of LAIV in pregnancy.
• LAIV is not contraindicated in breastfeeding (lactating) individuals; however, there are limited data for the use of LAIV in this population.
• People who are immunocompromised due to underlying disease and/or therapy; however, children living with stable HIV infection receiving antiretroviral therapy (ART) and with adequate immune function can receive LAIV.

Precautions

• Influenza vaccination should usually be postponed in people with serious acute illnesses until their symptoms have abated.
• NACI generally recommends people who have developed Guillain-Barré Syndrome (GBS) within 6 weeks of a previous influenza vaccination should not receive influenza vaccine unless another cause was found for the GBS.
  • The potential risk for a recurrent episode of GBS associated with influenza vaccination must be balanced against the risk of GBS associated with influenza infection itself and the benefits of influenza vaccination.
• For LAIV, NACI additionally recommends precautions for the following situations:
  • In the presence of significant nasal congestion or discharge that might impede delivery of LAIV to the nasopharyngeal mucosa;
  • For close contacts of people with severe immune compromising conditions; and
  • When there is administration of antivirals active against influenza (for example, oseltamivir, zanamivir).
• Contraindications or precautions related to LAIV administration should not be used as a reason to withhold or delay immunization with an alternate vaccine. In such cases, a parenteral inactivated or recombinant influenza vaccine can be offered.

More information on contraindications and precautions can be found in the Vaccine safety and adverse events section and in the Influenza vaccine chapter of the Canadian Immunization Guide's section on contraindications and precautions.

Why

• Influenza is a common vaccine-preventable disease. Vaccination is the most effective way to prevent influenza and its complications.
• Vaccination can help prevent the spread of influenza from person-to-person.
• Although most people will recover fully from influenza infection in 7 to 10 days, influenza can lead to severe disease, complications, or both, including hospitalization and death.
• Annual vaccination is required because the specific strains in the vaccine are reviewed each year by WHO and are often changed to provide a better match against the viruses expected to circulate in that given year, and the body's immune response to influenza vaccination may be transient and may not persist beyond a year.

New or updated information for 2025–2026

Transition from quadrivalent to trivalent influenza vaccines

NACI recommends that any age-appropriate quadrivalent or trivalent influenza vaccine should be used for individuals 6 months of age and older who do not have contraindications or precautions.

• Both quadrivalent and trivalent formulations are clinically safe and effective.
• B/Yamagata lineage viruses have not been detected globally since March 2020.
• Following this change in epidemiology, expert groups have endorsed the exclusion of the B/Yamagata component from influenza vaccine formulations, in alignment with WHO's recommendations for the 2024-2025 Northern Hemisphere season.

Quadrivalent vaccines were previously preferred for children due to the additional protection conferred by the presence of components from both influenza B lineages. NACI no longer has a preference between quadrivalent and trivalent influenza vaccine formulations for children.

For more information supporting this recommendation, refer to the Addendum to the statement on seasonal influenza vaccine for 2024-2025: Transition from quadrivalent to trivalent influenza vaccines and the section Choice of seasonal influenza vaccine of this statement.

Concurrent administration of influenza vaccines

A literature review was conducted in December 2023 to identify new evidence on efficacy, effectiveness, immunogenicity, and safety of concurrent administration of COVID-19 vaccines with other vaccines, including influenza vaccines, in individuals 6 months of age and older. A detailed evidence synthesis was included in NACI guidance on the use of COVID-19 vaccines during the fall of 2024 and a summary of the findings has been integrated in this statement. This update includes new evidence on the effects of concurrent administration of COVID-19 vaccines and influenza vaccines derived from RCTs and observational studies.

Additionally, a rapid review was conducted in May 2024 to retrieve evidence on the impact of concurrent administration of newer (for example, mRNA COVID-19) or adjuvanted vaccines with enhanced influenza vaccines (that is, IIV-Adj, IIV-HD, IIV-cc or RIV) on vaccine efficacy/effectiveness, immunogenicity, and safety. Considering the additional evidence identified through this review, NACI has updated this statement to include new information on the safety and immunogenicity of adjuvanted or high dose influenza vaccines when concurrently administered with other adjuvanted or newer vaccines.

There is no change to the recommendation that influenza vaccines may be administered concurrently with (that is, same day) or at any time before or after other inactivated or live attenuated vaccines.

Paramedic considerations

Influenza vaccine

According to NACI, the influenza vaccine is particularly recommended for those who are “capable of transmitting influenza to those at high risk, [and] people who provide essential community services.”

“NACI recommends that any age-appropriate IIV or RIV but not LAIV, should be offered to HCWs. [Health Care Workers]”.^{footnote 1[1]}

Influenza information for paramedics

The following is additional influenza related information for health professionals from the Government of Canada website:

What health professionals need to know about influenza

• Influenza is a respiratory illness caused primarily by the influenza A and B viruses.
• While most people recover in 7 to 10 days, severe illness can occur. Some groups are at a greater risk of influenza-related complications.
• It is estimated that influenza causes on average, 12,200 hospitalizations and 3,500 deaths in Canada each year.
• FluWatch, Canada's national influenza surveillance system, provides up-to-date information about currently circulating influenza strains
• Getting vaccinated against influenza each autumn is the best way to help prevent influenza infection.
• There are antiviral drugs currently authorized for influenza treatment and/or prophylaxis in Canada. Additional information is available through Public Health Ontario.
• Additional information for health professionals regarding influenza can be found here.

Influenza control

For more information regarding the responsibilities of paramedics and ambulance service operators to mitigate the spread of influenza, please refer to the current Patient Care and Transportation Standards (PCTS) for more information regarding Communicable Disease Management (Part B) and Influenza Control (Part C).

Oxygen administration for patients with symptoms of respiratory infection

The patient will wear:

• a surgical mask, if tolerated, with a nasal cannula if low concentration oxygen is required;
• low flow/high concentration oxygen mask outfitted with a hydrophobic submicron filter if high concentration oxygen is required;
• for patients requiring ventilatory assistance using a face mask or an endotracheal tube (ETT), a tube extender and a hydrophobic submicron filter shall be used. A tube extender is not necessary for pediatric patients and must not be used for any infants (< 1 year old).

Use of antiviral agents for influenza prevention

Several antiviral medications have been approved by the Public Health Agency of Canada for prophylactic use in the prevention of influenza virus infections. As with all prescription medications, the decision to use antiviral agents rests with individual’s physician. Paramedics who have had direct contact with a person suspected of having influenza are encouraged to consult their personal physician regarding the potential use of antiviral medication. For optimal effectiveness, antivirals should be initiated within 48 hours of exposure to an ill, infectious individual. Antivirals can help reduce the severity of the illness and the recovery time. ^{footnote 2[2]} Paramedics should review the PCTS v2.7 Section C – Influenza Control in relation to requirements for unvaccinated paramedics when providing patient care during declared outbreaks, including the use of antiviral medications and PPE.

Conclusion

This training bulletin outlines the personal, patient care, and public health benefits of an annual influenza vaccination. It also provides guidance on procedures to prevent exposure to influenza and to protect patients from exposure to influenza, along with other relevant information on influenza prevention.

Paramedics are encouraged to further review information regarding influenza and where appropriate, engage patients in discussions about influenza-related considerations, including vaccinations.