NACI Summary Influenza 2020-2021
Volume 46–5, May 7, 2020: Nosocomial infection surveillance
Advisory Committee Statement
Summary of the NACI Seasonal Influenza Vaccine Statement for 2020–2021
Kelsey Young1, Ian Gemmill2,3, Robyn Harrison4,5 on behalf of the National Advisory Committee on Immunization (NACI)
1 Centre for Immunization and Respiratory Infectious Diseases, Public Health Agency of Canada, Ottawa, ON
2 NACI Influenza Working Group Chair
3 Queen’s University, Kingston, ON
4 NACI Influenza Working Group Vice Chair
5 University of Alberta; Alberta Health Services, Edmonton, AB
Young K, Gemmill I, Harrison R, on behalf of the National Advisory Committee on Immunization (NACI). Summary of the NACI Seasonal Influenza Vaccine Statement for 2020–2021. Can Commun Dis Rep 2020;46(5):132–7. https://doi.org/10.14745/ccdr.v46i05a06
Keywords: National Advisory Committee on Immunization, NACI, influenza, influenza vaccine, guidance
Background: Evidence on influenza vaccination is continually evolving. The National Advisory Committee on Immunization (NACI) provides annual recommendations to the Public Health Agency of Canada regarding the use of seasonal influenza vaccines.
Objective: To summarize NACI’s recommendations regarding the use of seasonal influenza vaccines for the 2020–2021 influenza season and to highlight new and updated recommendations.
Methods: 1) To update wording on influenza vaccination of health care workers, NACI reassessed the evidence in the context of ethics and acceptability frameworks, in accordance with NACI’s recently expanded mandate. 2) To provide recommendations on the use of live attenuated influenza vaccine (LAIV) in HIV-infected individuals, the Influenza Working Group developed a predefined search strategy to identify all eligible studies, then assessed the quality and summarized and analyzed the findings according to the NACI evidence-based process. NACI provided new recommendations based on assessment of the evidence.
Results: 1) NACI continues to recommend that health care workers and other care providers in facilities and community settings should be vaccinated annually against influenza and that this group be included among those particularly recommended to receive the influenza vaccine. 2) NACI concluded that LAIV is immunogenic in children with stable HIV infection; therefore, NACI newly recommends that LAIV may be considered as an option for children 2–17 years of age with stable HIV infection on highly active antiretroviral therapy and with adequate immune function.
Conclusion: NACI continues to recommend that an age-appropriate influenza vaccine should be offered annually to anyone six months of age and older who does not have contraindications to the vaccine, with a focus on the groups for whom influenza vaccination is particularly recommended.
Seasonal influenza epidemics lead to significant morbidity and mortality in the Canadian populationFootnote 1 and cause significant strain on the health care system during the influenza season each year. Although the epidemiology of influenza varies from year to year, it is estimated that influenza infections cause an average of 12,200 hospitalizationsFootnote 2 and 3,500 deathsFootnote 3 per year.
Given the cyclical nature of seasonal influenza, the frequent changes to the circulating viral strains, and the number of influenza vaccines authorized for use in Canada, the National Advisory Committee on Immunization (NACI) provides annual recommendations regarding seasonal influenza vaccination to the Public Health Agency of Canada (PHAC). For the 2020–2021 influenza season, NACI has updated the wording used for their recommendation on the vaccination of health care workers (HCW) and has provided a new recommendation on the use of live attenuated influenza vaccine (LAIV) in HIV-infected individuals. Complete details on influenza vaccine can be found in the NACI Statement on Seasonal Influenza Vaccine for 2020–2021Footnote 4 and related publications. The objective of this article is to provide a concise summary of the information contained in this annual seasonal influenza statement and to highlight important updates.
Influenza vaccine abbreviations
The abbreviations used by NACI have been recently updated to better describe the defining features of the various types of influenza vaccines. The current abbreviations are listed in Table 1.
|Influenza vaccine category||Formulation||Type||Current NACI abbreviationFootnote a of Table 1|
|Inactivated influenza vaccine (IIV)||Trivalent (IIV3)||Standard doseFootnote b of Table 1, unadjuvanted, IM administered||IIV3-SD|
|AdjuvantedFootnote c of Table 1, IM administered||IIV3-Adj|
|High doseFootnote d of Table 1, unadjuvanted, IM administered||IIV3-HD|
|Quadrivalent (IIV4)||Standard doseFootnote b of Table 1, unadjuvanted, IM administered||IIV4-SD|
|Live attenuated influenza vaccine (LAIV)||Quadrivalent (LAIV4)||Unadjuvanted, Nasal spray||LAIV4|
To prepare the Statement on Seasonal Influenza Vaccine for 2020–2021, the Influenza Working Group identified the need for evidence reviews for two topics in particular and, following a review and analysis of the information, proposed new or updated recommendations according to the NACI evidence-based processFootnote 5. NACI critically appraised the available evidence and approved the specific recommendations brought forward.
Vaccination of health care workers and other care providers
NACI identified a need to reassess the wording used for the recommendation on the vaccination of HCWs and other care providers with the influenza vaccine. To inform this updated wording, the evidence from four cluster randomized controlled trialsFootnote 6Footnote 7Footnote 8Footnote 9 that assessed the impact of HCW influenza vaccination in geriatric long-term care settings was reassessed and considered in the context of ethics and acceptability. Ethics and acceptability were systematically considered, based on NACI’s approved methods for the evaluation of ethics, equity, feasibility and acceptability as part of NACI’s recently expanded mandate.
Use of live attenuated influenza vaccine in HIV-infected individuals
The NACI Influenza Working Group oversaw the completion of a systematic review to inform the development of guidance on the use of LAIV in HIV-infected individuals. Six electronic databases (MEDLINE, EMBASE, Scopus, ProQuest Public Health Database, ClinicalTrials.gov and PROSPERO) were searched from inception to April 13, 2018 to identify relevant literature on the efficacy, effectiveness, immunogenicity and safety of LAIV in HIV-infected adults and children aged six months and older. The Canadian Adverse Events Following Immunization Surveillance System (CAEFISS) was also searched to identify any reports received on adverse events following vaccination with LAIV in HIV-infected individuals. Two reviewers independently screened the titles and abstracts of records retrieved from the search and eligible full-text articles for inclusion. One reviewer extracted data from eligible studies and appraised the methodological quality of these studies using the criteria outlined by Harris et al.Footnote 10. A second reviewer validated the data extraction and quality assessment. A narrative synthesis of the extracted data was performed.
Vaccination of health care workers and other care providers
Based on their reassessment of the evidence in the context of ethics and acceptability, NACI continues to recommend that, in the absence of contraindications, HCWs and other care providers in facilities and community settings should be vaccinated annually against influenza. HCWs and other care providers have the potential to transmit influenza to individuals at high risk and, due to their occupation and close contact with people at high-risk of influenza-related complications, are themselves at increased risk of infectionFootnote 11. Given the potential to transmit influenza and the increased risk of infection, and knowing that vaccination is the most effective way to prevent influenza, NACI recommends the inclusion of this group among those particularly recommended to receive the influenza vaccine. NACI considers the receipt of influenza vaccination to be an essential component of the standard of care for all HCWs and other care providers for their own protection and that of their patients. This group should consider annual influenza vaccination as part of their responsibilities to provide the highest standard of care.
Further information on NACI’s recommendation for the inclusion of HCWs as a group for whom influenza vaccination is particularly recommended can be found in Section III.2 of the NACI Seasonal Influenza Vaccine Statement for 2020–2021Footnote 4.
Use of live attenuated influenza vaccine in HIV-infected individuals
The systematic review identified eight articles that reported the findings from five studies investigating the immunogenicity, the safety, or both, of the administration of LAIV in HIV-infected individuals. No studies investigating the efficacy or effectiveness of LAIV in this population were identified. Based on the identified evidence, NACI concluded that LAIV is immunogenic in children with stable HIV infection on highly active antiretroviral therapy (HAART) and with adequate immune function. NACI also concluded that, while there is insufficient direct evidence to detect uncommon or rare adverse events related to the use of LAIV in HIV infected children, LAIV appears to have a similar safety profile to inactivated influenza vaccine (IIV). In addition, some children and their substitute decision-makers may prefer that they receive influenza vaccine through an intranasal spray as opposed to an intramuscular (IM) injection, although preferences will vary. Regarding the use of LAIV in HIV-infected adults, NACI concluded that the quantity of evidence available on the immunogenicity and safety of LAIV in adults with HIV is insufficient to justify a recommendation for the use of LAIV in this age group. Based on their assessment of the evidence, NACI has made the following recommendation:
NACI recommends that LAIV may be considered as an option for children 2–17 years of age with stable HIV infection on HAART and with adequate immune function* (Discretionary NACI recommendation).
*LAIV should only be considered in children with HIV who meet the following criteria:
- receiving HAART for ≥4 months
- CD4 count ≥500/µL if 2–5 years of age, or ≥200/µL if 6–17 years of age (measured within 100 days before administration of LAIV)
- HIV plasma RNA <10,000 copies/mL (measured within 100 days before administration of LAIV)
While IM influenza vaccination is still considered the standard for children living with HIV by NACI and the Canadian Pediatric and Perinatal HIV/AIDS Research Group, LAIV would be reasonable for children meeting the criteria outlined above, if IM vaccination is not accepted by the patient or substitute decision-maker.
The detailed findings of this review and additional information supporting this recommendation can be found in the NACI Statement on the Recommendation on the Use of Live-Attenuated Influenza Vaccine (LAIV) in HIV-Infected IndividualsFootnote 12.
Summary of NACI recommendations for the use of influenza vaccines for the 2020–2021 influenza season
NACI continues to recommend influenza vaccination to anyone six months of age and older who does not have contraindications to the vaccine. Vaccination should be offered as a priority to people at high risk of influenza-related complications or hospitalization, people capable of transmitting influenza to those at high risk of complications, and others as indicated in List 1.
List 1: Groups for whom influenza vaccination is particularly recommended
People at high risk of influenza-related complications or hospitalization:
- All pregnant women
- Adults and children with the following chronic health conditionsFootnote a of List 1:
- Cardiac or pulmonary disorders (includes bronchopulmonary dysplasia, cystic fibrosis and asthma)
- Diabetes mellitus and other metabolic diseases
- Cancer, immune compromising conditions (due to underlying disease, therapy or both, such as solid organ transplant or hematopoietic stem cell transplant recipients)
- Renal disease
- Anemia or hemoglobinopathy
- Neurologic or neurodevelopmental conditions (includes neuromuscular, neurovascular, neurodegenerative and neurodevelopmental conditions and seizure disorders [for children, includes febrile seizures and isolated developmental delay], but excludes migraines and psychiatric conditions without neurological conditions)
- Morbid obesity (body mass index [BMI] of 40 and over)
- Children six months to 18 years of age undergoing treatment for long periods with acetylsalicylic acid, because of the potential increase of Reye’s syndrome associated with influenza
- People of any age who are residents of nursing homes and other chronic care facilities
- Adults 65 years of age and older
- All children 6–59 months of age
- Indigenous people
People capable of transmitting influenza to those at high risk:
- Health care and other care providers in facilities and community settings who, through their activities, are capable of transmitting influenza to those at high risk
- Household contacts, both adults and children, of individuals at high risk, whether or not the individual at high risk has been vaccinated, including:
- Household contacts of individuals at high risk
- Household contacts of infants less than six months of age, as these infants are at high risk but cannot receive influenza vaccine
- Members of a household expecting a newborn during the influenza season
- Those providing regular child care to children 0–59 months of age, whether in or out of the home
- Those who provide services within closed or relatively closed settings to people at high risk (e.g. crew on a ship)
- People who provide essential community services
- People who are in direct contact with poultry infected with avian influenza during culling operations
|Recipient by age group||Vaccine types authorized for use||Recommendations on choice of influenza vaccine|
|2–17 yearsFootnote b of Table 2||
|65 years and olderFootnote c of Table 2||
|Age group||Influenza vaccine type (route of administration)||Number of doses required|
|IIV3-SDFootnote a of Table 3 or IIV4-SDFootnote b of Table 3 (Intramuscular)||IIV3-AdjFootnote c of Table 3 (Intramuscular)||IIV3-HDFootnote d of Table 3 (Intramuscular)||LAIV4Footnote e of Table 3 (Intranasal)|
|6–23 months||0.5 mLFootnote f of Table 3||0.25 mL||–||–||1–2Footnote g of Table 3|
|2–8 years||0.5 mL||–||–||0.2 mL (0.1 mL per nostril)||1–2Footnote g of Table 3|
|9–17 years||0.5 mL||–||–||0.2 mL (0.1 mL per nostril)||1|
|18–59 years||0.5 mL||–||–||0.2 mL (0.1 mL per nostril)||1|
|60–64 years||0.5 mL||–||–||–||1|
|65 years and older||0.5 mL||0.5 mL||0.5 mL||–||1|
NACI continues to recommend annual influenza vaccination for all individuals aged six months and older (noting product-specific age indications and contraindications), with particular focus on people at high risk of influenza-related complications or hospitalization. In addition, people capable of transmitting to high risk individuals, people who provide essential community services and people in direct contact during culling operations with poultry infected with avian influenza are particularly recommended to receive the influenza vaccine. For the 2020–2021 influenza season, NACI continues to recommend that, in the absence of contraindications, HCWs and other care providers in facilities and community settings should be vaccinated annually against influenza, and continues to recommend the inclusion of this group among those particularly recommended to receive the influenza vaccine. NACI also newly recommends that LAIV may be considered as an option for children 2–17 years of age with stable HIV infection HAART and with adequate immune function.
- KY — Writing, original draft, review, editing
- IG — Review, editing
- RH — Review, editing
The National Advisory Committee on Immunization (NACI) Canadian Immunization Guide Chapter on Influenza and Statement on Seasonal Influenza Vaccine for 2020–2021 was prepared by K Young, A Sinilaite, L Zhao, and I Gemmill on behalf of the NACI Influenza Working Group and was approved by NACI.
Conflict of interest
Influenza Working Group members: I Gemmill (Chair), R Harrison (Vice-Chair), C Bancej, L Cochrane, N Dayneka, L Grohskopf, D Kumar, J Langley, P Wolfe-Roberge, J McElhaney, A McGeer, D Moore, S Smith, B Warshawsky and J Xiong
NACI members: C Quach (Chair), S Deeks (Vice-Chair), N Dayneka, P De Wals, V Dubey, R Harrison, K Hildebrand, C Rotstein, M Salvadori, B Sander, N Sicard and S Smith
Liaison representatives: LM Bucci (Canadian Public Health Association), E Castillo (Society of Obstetricians and Gynaecologists of Canada), A Cohn (Centers for Disease Control and Prevention, United States), J Emili (College of Family Physicians of Canada), M Naus (Canadian Immunization Committee), D Moore (Canadian Paediatric Society) and A Pham-Huy (Association of Medical Microbiology and Infectious Disease Canada)
Ex-officio representatives: J Gallivan (Marketed Health Products Directorate, Health Canada [HC]), E Henry (Centre for Immunization and Respiratory Infectious Diseases [CIRID], Public Health Agency of Canada [PHAC]), M Lacroix (Public Health Ethics Consultative Group, PHAC), J Pennock (CIRID, PHAC), R Pless (Biologics and Genetic Therapies Directorate, HC), G Poliquin (National Microbiology Laboratory, PHAC) and T Wong (First Nations and Inuit Health Branch, Indigenous Services Canada)
The National Advisory Committee on Immunization acknowledges and appreciates the contribution of O Baclic, A House, S Ismail, M Laplante and M Tunis to this statement.
The work of the National Advisory Committee on Immunization is supported by the Public Health Agency of Canada.
This work is licensed under a Creative Commons Attribution 4.0 International License
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