Vaccine recommendations for children and youth for the 2026/2027 influenza season

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Paediatricians and other health care providers caring for children and youth have important roles in promoting influenza vaccination. They can increase the uptake of influenza vaccine (Inf-v) by helping families recognize both the potential severity of influenza infection and the efficacy and safety of vaccination. Vaccination against influenza is especially important to minimize the impacts of influenza severity on individual children and families as well as on health care systems.

This practice point summarizes recent recommendations from the National Advisory Committee on Immunization (NACI), the epidemiology of the 2025/26 influenza season in Canada, and vaccine formulations changes for the 2026/27 season ^[1]-[3].

Why should children be vaccinated against influenza?

Influenza imposes a significant disease burden on children. Children under 5 years of age are recognized to be at high risk of influenza-related complications or hospitalization. Infants, especially those under 6 months old, are disproportionately vulnerable to influenza severity because they neither have prior immunity, nor are they eligible for the vaccine ^[1].

The 2025/26 influenza season in Canada was dominated by influenza A(H3N2) and showed an early peak in December, when children and adolescents accounted for a large proportion of influenza activity. Depending on circulating strains, the burden in children can fluctuate from season to season. Over the 2025/26 season, there were just under 1500 paediatric hospitalizations and eight paediatric influenza-attributed deaths ^[2].

Despite substantial antigenic drift during the past season (and resulting antigenic mismatch), protection estimates have highlighted that the risk of medically attended A(H3N2) influenza illness was reduced by 40% among vaccinated individuals compared with unvaccinated individuals over the 2025/26 season ^[4].

Who should be vaccinated?

NACI recommends Inf-v for all individuals ≥6 months of age, with particular focus on people at high risk for influenza-related complications or hospitalization, and individuals capable of transmitting influenza to those at high risk (Box 1) ^[1]. The Canadian Paediatric Society (CPS) encourages annual influenza vaccination for ALL children and youth ≥6 months of age, as well as adults—including paediatricians and other health care providers—who may transmit influenza to those at high risk ^[1]. Children younger than 5 years of age are considered to be at high risk and, in addition, are efficient transmitters of influenza ^[5].

Why vaccinate annually?

The recommended composition of influenza vaccines for the Northern Hemisphere in 2026/27 is different from the 2025/26 vaccines, with different virus components: A(H1N1)pdm09, A(H3N2), and B/Victoria ^[3].

Since March 2020, the B/Yamagata lineage has disappeared worldwide, and only the B/Victoria lineage has been circulating. The B/Yamagata lineage was removed from the annual Inf-v after 2023 and the transition from quadrivalent vaccine to trivalent vaccine followed ^[1].

In children, vaccine-induced protection remains robust and relatively stable over a typical influenza season. Antibody titers peak one month post-vaccination and decline gradually over time but generally remain above seroprotective levels for at least 6 months. However, while evidence supports high vaccine effectiveness against seasonal influenza activity, immune response to influenza vaccine may not persist beyond a year. Circulating strains change frequently, such that season-to-season protection is not guaranteed ^[1].

What vaccine should be used?

Two types of Inf-v are licensed in Canada: inactivated influenza vaccines (IIV) for intramuscular (IM) injection and an intranasal (IN) live attenuated influenza vaccine (LAIV) (see Table 1). All are trivalent formulations (IIV3 and LAIV3) ^[1].

There are two broad categories of IIV available in Canada: 1) vaccines produced in eggs (described as standard-dose [SD], high-dose [HD], and adjuvanted); and 2) a vaccine produced in mammalian cell cultures (IIV3-cc), which is authorized for use in individuals ≥6 months of age. The egg-based adjuvanted IIV3 (IIV3-Adj) is available for children 6 to 23 months of age and for adults ≥65 years ^[1].

One LAIV is currently authorized and available for use in Canada for children 2 to 17 years of age and adults 18 to 59 years of age: LAIV3, a trivalent IN spray vaccine administered as a 0.2 mL dose (0.1 mL in each nostril). LAIV is not licensed for use in children <2 years of age because of an observed small, but significant, increased rate of wheezing 2 to 4 weeks following vaccination. LAIV can be used for children and youth 2 to 17 years of age who are not immunocompromised. LAIV should not be used in children who are immunocompromised because this live vaccine contains attenuated influenza viruses that are replication competent and therefore carry a theoretical risk of vaccine-associated disease ^[1].

Studies have shown comparable protection in children with LAIV and IIV. For children without contraindications to LAIV, either vaccine may be used ^[1]. In adults, there is some evidence that IIV may be more efficacious than LAIV. Either IIV or LAIV may be used for healthy adults, but adults with chronic health conditions should receive IIV ^[1]. In children with human immunodeficiency virus (HIV), NACI states that although IIV is preferred, LAIV may be considered in selected children with well-controlled HIV who will not accept IIV (see Table 1 footnote for definitions of well-controlled HIV) ^[1].

Vaccine options and NACI preferences for children and youth are shown in Table 1 ^[1].

When to vaccinate

For maximum benefit, Inf-v should be given as soon as it is available, before the onset of the influenza season. Nevertheless, Inf-v should be offered up to the end of the current influenza season to individuals who have not received it ^[1].

Are there any contraindications to influenza vaccine?

An anaphylactic reaction to a previous dose of Inf-v or to any of the components of the vaccine (with the exception of egg), or onset of Guillain-Barré syndrome within 6 weeks of influenza vaccination without another known cause, are contraindications to further doses ^[1].

Studies have shown that IIV and LAIV can be given safely to egg-allergic individuals. Egg allergy is not a contraindication to administering either IIV or LAIV. Inf-v should always be given in a setting where anaphylaxis can be managed ^[1].

LAIV, because it is a live vaccine, is contraindicated in immunocompromised individuals. The exception is children with stable HIV infection, for whom LAIV may be considered. LAIV is also contraindicated for individuals with severe asthma (defined as current active wheezing or currently on oral or high-dose inhaled glucocorticosteroids, or medically attended wheezing within the previous 7 days), during pregnancy, and in children and adolescents 2 to 17 years of age, who are receiving chronic acetylsalicylic acid-containing therapy, because Reye’s syndrome has been associated with acetylsalicylic acid given during influenza infection ^[1].

For individuals experiencing nasal congestion sufficient to impede appropriate delivery of LAIV, vaccination should be deferred until the congestion has resolved, or IIV should be given ^[1].

Spread of the vaccine virus from persons immunized with LAIV can occur; however, the virus is cold-adapted and, therefore, not very pathogenic. As a precaution, it is recommended that contact with severely immunocompromised patients (such as recent hematopoietic stem cell transplant recipients who still require isolation) be avoided for 2 weeks following receipt of LAIV. IIV is preferred for health care workers, family members, and others who will be in close contact with such individuals ^[1].

Can influenza vaccine be given at the same time as other vaccines or antiviral products?

Any seasonal Inf-v may be given at the same time as, or any time before or after, any other vaccine(s) or respiratory syncytial virus monoclonal antibodies such as nirsevimab or clesrovimab ^[6].

LAIV should not be administered until 48 hours after antiviral agents active against influenza have been discontinued because these antivirals will inactivate the vaccine virus. If an anti-influenza agent must be given within 2 weeks after receipt of LAIV, another dose of vaccine should be administered at least 48 hours after discontinuation of therapy, or IIV should be substituted ^[1].

What is the dosage?

The dose of IIV administered IM is 0.5 mL, regardless of age, except for paediatric IIV3-Adj, for which the dose is 0.25 mL IM. The dose of LAIV is 0.2 mL (0.1 mL administered in each nostril as an intranasal spray) ^[1].

The first year that a child younger than 9 years of age receives Inf-v (IIV or LAIV), two doses at least 4 weeks apart are required. If a child less than 9 years of age has received at least one dose of any Inf-v in the past, only one dose is required this season. Children ≥9 years of age and adults require only one dose each year ^[1].

CANADIAN PAEDIATRIC SOCIETY INFECTIOUS DISEASES AND IMMUNIZATION COMMITTEE (2025-2026)

Members: Michelle Barton MD (Chair), Laura Sauvé MD (Past Chair), Eugene Ng MD (Board Representative), Ari Bitnun MD, Sergio Fanella MD, Laura Erdman MD, Jeannette Comeau MD MSc
Liaisons: Cora M Constantinescu MD (National Advisory Committee on Immunization), Sean Bitnun MD (Canadian Paediatric and Perinatal HIV/AIDS Research Group), Isabelle Viel-Thériault MD (Committee to Advise on Tropical Medicine and Travel), Marina Salvadori MD (Public Health Agency of Canada), Sean O’Leary (American Academy of Pediatrics, Committee on Infectious Diseases), Rupeena Purewal MD (Immunization Monitoring Program, ACTive), Jennifer Tam MD (Association of Medical Microbiology and Infectious Disease Canada, Pediatric Committee)
Principal author: Cora M Constantinescu MD

References

1. Public Health Agency of Canada. National Advisory Committee on Immunization (NACI). An Advisory Committee Statement (ACS): Statement on Seasonal Influenza Vaccines for 2026–2027. May 12, 2026 (Accessed July 22, 2026).
2. Government of Canada. Influenza: Canadian Respiratory virus surveillance Report. Health Infobase. Last updated June 26, 2026 (Accessed July 22, 2026).
3. World Health Organization. Recommended Composition of Influenza Virus Vaccines for Use in the 2026–2027 Northern Hemisphere Influenza Season. February 27, 2026, Technical document. (Accessed July 22, 2026).
4. Separovic L, Sabaiduc S, Zhan Y, et al. Interim 2025/26 influenza vaccine effectiveness estimates with immuno-epidemiological considerations for A(H3N2) subclade K protection, Canada, January 2026. Euro Surveill 2026;31(5):2600068. doi: 10.2807/1560-7917.ES.2026.31.5.2600068
5. Hurwitz ES, Haber M, Chang A, et al. Effectiveness of influenza vaccination of day care children in reducing influenza-related morbidity among household contacts. JAMA 2000;284(13):1677-82. doi: 10.1001/jama.284.13.1677
6. Public Health Agency of Canada. National Advisory Committee on Immunization (NACI). An Advisory Committee Statement (ACS): Updated guidance to protect infants and children from respiratory syncytial virus (RSV) disease; Use of monoclonal antibodies (nirsevimab and clesrovimab) and the RSVpreF vaccine (Accessed July 22, 2026).April 2026.

Disclaimer: The recommendations in this position statement do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate. Internet addresses are current at time of publication.