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Canadian Paediatric Society

Practice Point

Vaccine recommendations for children and youth for the 2018/2019 influenza season

Posted: Sep 28 2018

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Principal author(s)

Dorothy L. Moore; Canadian Paediatric Society, Infectious Diseases and Immunization Committee


The Canadian Paediatric Society continues to encourage annual influenza vaccination for ALL children and youth ≥6 months of age. Recommendations from the National Advisory Committee on Immunization (NACI) for the 2018/2019 influenza season are not substantially changed from those of last season. Quadrivalent vaccine, if available, is recommended for children 6 months to 17 years of age. Either inactivated influenza vaccine or live attenuated influenza vaccine may be used for children and youth 2 to 17 years of age who are not immunocompromised.

Keywords: Children; Influenza vaccine; Inactivated influenza vaccine; LAIV; NACI

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 by helping families to recognize both the potential severity of influenza infection, and the efficacy and safety of vaccination.


The Canadian Paediatric Society encourages annual influenza vaccinations for ALL children and youth ≥6 months of age, with a particular focus on individuals at high risk for influenza-related complications and people—including paediatricians and other health care providers—capable of transmitting influenza to those at high risk (Box 1). All children younger than 5 years of age are considered to be at high risk for infection and, in addition, are efficient transmitters of influenza [1].

This practice point summarizes the most recent recommendations from the National Advisory Committee on Immunization (NACI) [1]. Beginning in the 2014/2015 season, NACI recommended influenza vaccine 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].

Box 1. National Advisory Committee on Immunization recommendations for the 2018/2019 influenza season

Influenza vaccination is particularly recommended for the following groups:

People at high risk for influenza-related complications or hospitalization:

  • All children 6 to 59 months of age
  • All children ≥6 months of age, adolescents and adults with chronic health conditions (severe enough to require regular medical follow-up or hospital care), specifically:
    • Cardiac or pulmonary disorders, including bronchopulmonary dysplasia, cystic fibrosis, asthma
    • Diabetes mellitus and other metabolic diseases
    • Cancer, other immune-compromising conditions (due to underlying disease, therapy or both)
    • Renal disease
    • Anemia or hemoglobinopathy
    • Neurological or neurodevelopmental conditions*
    • Morbid obesity (body mass index ≥40 kg/m2)
    • Children and adolescents (6 months to 18 years of age) undergoing prolonged treatment with acetylsalicylic acid, because of the potential increase of Reye’s syndrome associated with influenza
  • Indigenous peoples
  • All residents of chronic care facilities
  • All pregnant women, including adolescents, in all trimesters (for their own protection and to protect their infant after birth)
  • All adults ≥65 years of age

People capable of transmitting influenza to individuals at high risk, specifically:

  • Household contacts (adults and children) of individuals at high risk (listed above), regardless of whether the person at risk has been immunized
  • Household contacts of infants <6 months of age (these infants are at high risk but too young to receive influenza vaccine)
  • Members of a household expecting a newborn during influenza season
  • Individuals providing regular child care to children ≤59 months of age, regardless of whether in or out of the home
  • Health care and other care providers in facilities and community settings
  • Others who provide services to individuals at high risk in closed or relatively confined settings


  • People who provide essential community services
  • People in direct contact during culling operations with poultry infected with avian influenza
* These include neuromuscular, neurovascular, neurodegenerative, neurodevelopmental conditions and seizure disorders, and for children, febrile seizures and isolated developmental delay, but excludes migraines and neuropsychiatric conditions without neurological abnormalities.


Although some vaccinated individuals retain immunity from one season to the next, this is less likely when the predominant circulating strain changes; therefore, annual revaccination is recommended. A high failure rate of the influenza vaccine was observed during the 2014/2015 season because of the appearance of an important antigenic change in the predominant circulating A H3N2 strain, rendering that component of the vaccine ineffective. That component and one influenza B component were replaced in 2015/2016 and again in 2016/2017. In 2017/2018, the influenza A H1N1 component was replaced. For the upcoming 2018/2019 season, the influenza A H3N2 component and one of the B vaccine components in the 2017/18 vaccine have been replaced [2]. Recent concerns about reduced vaccine efficacy after repeated vaccination are being investigated but data so far support continuing annual revaccination [1].


For several decades, influenza vaccines contained two subtypes of influenza A and one lineage of influenza B. Two lineages of influenza B have been in circulation simultaneously in recent years, and trivalent vaccines are now being replaced by quadrivalent vaccines containing two strains of influenza A and both lineages of influenza B. The NACI recommends preferential use of quadrivalent vaccines for children and adolescents because influenza B causes more mortality and morbidity in children than in adults [1].

Two types of influenza vaccines are available in Canada: inactivated influenza vaccines (IIV) for intramuscular injection and an intranasal, live attenuated influenza vaccine (LAIV).

IIV is available in quadrivalent (QIV) and trivalent (TIV) forms. An adjuvanted TIV (Fluad Pediatric, Seqirus Canada) is available for children 6 to 23 months of age, and may be used for this age group when QIV is not available. While adjuvants are designed to enhance vaccine immunogenicity, there is insufficient evidence at the present time to make a preferential recommendation for adjuvanted or unadjuvanted TIV.

LAIV is now available only in the quadrivalent form. It is authorized for use in individuals 2 to 59 years of age [1]. The most common side effects of LAIV are transient nasal congestion and rhinorrhea. LAIV is not licensed for use in children younger than 2 years of age because of a small, but significant, increased rate of wheezing 2 to 4 weeks following vaccination observed in this age group. LAIV can be used for children and youth, 2 to 17 years of age, who are not immunocompromised. In NACI statements up to 2015/2016, LAIV was preferred over IIV for children because early studies had shown LAIV to have greater efficacy than IIV. However, more recent studies have not consistently shown LAIV to provide better protection than IIV. NACI no longer recommends LAIV preferentially for children; either LAIV or IIV 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.

In the USA, data from the US Flu Vaccine Effectiveness Network (USFVEN) showed no protective effect of LAIV against influenza A H1N1 during the 2013/2014 through 2015/2016 seasons, prompting the American Advisory Committee on Immunization Practices (ACIP) to recommend that LAIV not be used for the 2016/2017 and 2017/2018 seasons. In contrast to the USFVEN results, LAIV was found to be effective in other studies in the USA, as well as in the UK, Finland and Canada, where LAIV continues to be used. After careful review of all available studies from the last several influenza seasons, NACI has concluded that the current evidence suggests that LAIV provides comparable protection against influenza to that of IIV in several jurisdictions, including Canada, and continues to recommend it as an option [1].

ACIP now reports that data from 2010/2011 through 2016/2017 indicate that LAIV was more effective than IIV against influenza B and equally effective against influenza A H3N2. LAIV’s effectiveness against influenza A H1N1 was poor, however. The A H1N1 strain in LAIV was found to replicate less well than expected and was replaced in 2017 with a more fit strain. For the 2018/2019 season, ACIP recommends that either LAIV or IIV may be used [3]. The American Academy of Pediatrics recommends that LAIV be used only if the child would not otherwise receive influenza vaccine [4].

In summary, quadrivalent influenza vaccine is recommended for all children. For nonimmunocompromised children 2 years of age or older, either IIV or LAIV may be used. See Table 1 for vaccine options and NACI preferences for children and youth. It is recognized that programmatic considerations may affect vaccine availability in publicly funded programs.

Table 1. Choice of influenza vaccine for selected age and risk groups*

Age group, health profile

Vaccine types available


Children 6 to 23 months of age




QIV should be used. If QIV is unavailable, TIV or ATIV should be used

Children 2 to 17 years of age: healthy or with chronic health conditions without immune suppression




A quadrivalent vaccine (Q-LAIV or QIV) should be used. If both Q-LAIV or QIV unavailable, TIV should be used

Children 2 to 17 years of age: immune compromising conditions



QIV should be used. If QIV is unavailable, TIV should be used

Q-LAIV is contraindicated




Q-LAIV is not recommended (not studied; theoretical risk to fetus of live vaccine)

*For vaccine options for adults see reference [1].

ATIV Adjuvanted trivalent inactivated influenza vaccineQIV Quadrivalent inactivated influenza vaccine; Q-LAIV Quadrivalent live attenuated influenza vaccine; TIV Trivalent inactivated influenza vaccine


For maximum benefit, influenza vaccine should be given as soon as it is available, before the onset of the influenza season. Nevertheless, it should be offered to individuals who have not received it earlier up until the end of the current season. Benefit may be less if exposure to influenza has already occurred.


An anaphylactic reaction to a previous dose of influenza vaccine 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 other known cause, are contraindications to further doses [1].

Since 2011/2012, egg allergy has not been a contraindication to the use of IIV. More recently, several studies have shown that LAIV can also be given safely to egg-allergic individuals and since 2016/2017, NACI no longer considers this condition a contraindication [1]. Either IIV or LAIV can be given to individuals with egg allergy. Like all other vaccines, influenza vaccine should be given in a setting where anaphylaxis can be managed [1][3].

LAIV, because it is a live vaccine, is contraindicated in individuals with immunocompromising conditions. 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) and during pregnancy. LAIV is also contraindicated in children and adolescents, 2 to 17 years of age, who are receiving chronic acetylsalicylic acid-containing therapy, because of the association of Reye’s syndrome with acetylsalicylic acid given during influenza infection.

LAIV should not be administered until 48 h after antiviral agents active against influenza have been discontinued. If an antiviral agent must be given within 2 weeks after the receipt of LAIV, another dose of vaccine should be given at least 48 h after discontinuation of therapy or IIV should be given. For individuals experiencing nasal congestion sufficient to impede the appropriate delivery of LAIV, vaccination should be deferred until the congestion has resolved or IIV should be given.

Spread of the 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 are still in hospital) be avoided for 2 weeks following receipt of LAIV.


The dose of IIV administered intramuscularly (IM) is 0.5 mL, regardless of age, except for paediatric adjuvanted TIV, for which the dose is 0.25 mL IM. The dose of Q-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 influenza vaccine (either IIV or Q-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 influenza vaccine in the past, only one dose is required this season. Children ≥9 years of age and adults require only one dose each year.


Members: Michelle Barton-Forbes MD; Sean Bitnun MD; Natalie A Bridger MD (past member); Shalini Desai MD (past member); Michael Forrester MD; Ruth Grimes MD (Board Representative); Nicole Le Saux MD (Chair); Karina Top MD

Liaisons: Upton D Allen MBBS, Canadian Pediatric AIDS Research Group; Tobey Audcent MD, Committee to Advise on Tropical Medicine and Travel (CATMAT), Public Health Agency of Canada; Carrie Byington MD, Committee on Infectious Diseases, American Academy of Pediatrics; Marc Lebel MD, IMPACT (Immunization Monitoring Program, ACTIVE); Jane McDonald MD, Association of Medical Microbiology and Infectious Disease Canada; Dorothy L. Moore MD, National Advisory Committee on Immunization (NACI); Howard Njoo MD, Public Health Agency of Canada

Consultant: Noni E. MacDonald MD

Principal author: Dorothy L. Moore MD


  1. National Advisory Committee on Immunization. An Advisory Committee Statement. Canadian Immunization Guide Chapter on Influenza and Statement on Seasonal Influenza Vaccine for 2018–2019: (Accessed September 1, 2018).
  2. Grohskopf LA, Sokolow LZ, Broder KR, Walter EB, Fry AM, Jernigan DB. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season. MMWR Recommendations and Reports2018;67(3):1–20: (Accessed September 1, 2018).
  3. Grohskopf LA, Sokolow LZ, Fry AM, Walter EB, Jernigan DB. Update: ACIP recommendations for the use of quadrivalent live attenuated influenza vaccine (LAIV4)—United States, 2018–19 influenza season. MMWR 2018;67(22):643–5: (Accessed September 1, 2018).
  4. American Academy of Pediatrics, Committee on Infectious Diseases. Recommendations for prevention and control of influenza in children, 2018–2019. Pediatrics 2018;142(4):e20182367.

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.

Last updated: Sep 28 2018