The Underappreciated Burden of Influenza Among Canada's Older Population. And What We Need to Do About It.
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
The Underappreciated
Burden of Influenza
Among Canada’s
Older Population.
And What We
Need to Do
About It.
$
$
$
November, 2018
Updated January 2022National Institute on Ageing Immunization Series Suggested Citation: National Institute on Ageing. (2021). The underappreciated burden of influenza among Canada’s older population. And what we need to do about it. Toronto, ON: National Institute on Ageing White Paper. Copyright © National Institute on Ageing at Ryerson University, Ryerson University, Toronto ISBN 978-1-926769-83-7 ISSN 2561-4827 (Print) ISSN 2561-4835 (Online) Mailing Address: National Institute on Ageing Ted Rogers School of Management 350 Victoria St. Toronto, Ontario M5B 2K3 Canada Disclaimer: The NIA has developed this document to provide a summary of general information about the burden of influenza and the benefit of the influenza vaccine, as well as provide evidence- informed recommendations to support uptake of the influenza vaccine. The NIA’s work is guided by the current evidence. This document can be reproduced without permission for non-commercial purposes, provided that the NIA is acknowledged. Funding for this report was generously provided by Sanofi Canada in the form of an unrestricted educational grant. All of the research, writing and recommendations herein have been independently produced by the NIA on the basis of sound evidence.
NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
About the National
Institute on Ageing
The National Institute on Ageing (NIA) is a The NIA further serves as the academic
public policy and research centre based at home for the National Seniors Strategy
Ryerson University in Toronto. The NIA is (NSS), an evolving evidence-based policy
dedicated to enhancing successful ageing document co-authored by a group of
across the life course. It is unique in its leading researchers, policy experts and
mandate to consider ageing issues from a stakeholder organizations from across
broad range of perspectives, including Canada and first published in 2014.
those of financial, physical, psychological,
and social well-being. The NSS outlines four pillars that guide the
NIA’s work to advance knowledge and
The NIA is focused on leading inform policies through evidence-based
cross-disciplinary, evidence-based, and research around ageing in Canada:
actionable research to provide a blueprint Independent, Productive and Engaged
for better public policy and practices Citizens; Healthy and Active Lives; Care
needed to address the multiple challenges Closer to Home; and Support for Caregivers.
and oppor tunities presented by Canada’s
ageing population. The NIA is committed to
providing national leadership and public
education to productively and
collaboratively work with all levels of
government, private and public sector
partners, academic institutions,
ageing-related organizations, and
Canadians.
About the National Institute on Ageing 02NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Authors and Reviewers
The background research for this report was Dr. Allison McGeer – Medical Director,
undertaken by Julie Dunning (NIA Policy Infection Prevention and Control, Sinai
Analyst). It was written by Dr. Samir Sinha Health System and Professor of Laboratory
(Director of Geriatrics, Sinai Health System Medicine and Pathobiology and at the
and University Health Network; Associate Dalla Lana School of Public Health,
Professor of Medicine, Family and University of Toronto.
Community Medicine, Health Policy,
Dr. Janet McElhaney – HSN Volunteer
Management and Evaluation, University
Association Chair in Healthy Aging; VP
Toronto; Co-chair, NIA), Julie Dunning,
Research and Scientific Director; Health
Ivy Wong (NIA Senior Policy Advisor),
Sciences North Research Institute; Professor,
Stephanie Woodward (Former NIA
Northern Ontario School of Medicine.
Executive Director) and and Michael Nicin
(NIA Executive Director). This report was
Dr. Jacob Udell – Cardiovascular Division,
edited by Allan McKee (NIA
Women’s College Hospital & Peter Munk
Communications Officer). This report was
Cardiac Centre, Toronto General Hospital;
updated by Cameron Feil (NIA Research
Assistant Professor of Medicine, University
Coordinator) and Natalie Iciaszczyk (NIA
of Toronto.
Policy Analyst).
Expert Reviewers Expert Reviewers for Previous and
We would like to sincerely thank our expert Revised Version
reviewers for their thoughtful feedback
and guidance on the content and final Dr. Jeff Kwong – Program Leader,
recommendations of this report. Any Populations and Public Health Research
opinions or errors reflected in this report Program, ICES; Scientist, Public Health
are of the NIA alone. Ontario; Family Physician, Toronto Western
Hospital; Interim Director, Centre for
Dr. Michael Gardam – Medical Director,
Vaccine Preventable Disease, University of
Infection Prevention and Control, Women’s
Toronto; Professor, Department of Family &
College Hospital and Associate Professor of
Community Medicine and Dalla Lana School
Medicine, University of Toronto.
of Public Health, University of Toronto
Colin Busby – Research Director, IRPP
Authors and Reviewers 03Table of
Contents
02 03 05
About the National Authors and Executive
Institute on Ageing Reviewers Summary
16
07 14 The Influenza
Vaccination – Still
Background Vaccination – A Public Our Best Defence
and Context Health Success Story Against Influenza
24 25
Comparing Influenza
and COVID-19 Vaccine
24 Vaccination Policies
Uptake among Older Other Means and Outcomes in
Adults in Canada of Prevention Canada
33 35
32 Health Care Provider Vaccination Rates for
Vaccination Rates Influenza Vaccination Health Care Providers/
in Canada Policies in Canada Health Care Facilities
42 47 56
Vaccine Evidence–Informed
Hesitancy Recommendations ReferencesNIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Executive Summary average of 3,500 deaths each year. 6
Influenza and pneumonia are the 7th
While Canada recommends an influenza leading cause of death in Canada 7 and the
vaccination target of 80% for those aged 65 leading cause of death among vaccine
years and older 1, only approximately 70% of preventable diseases. 8
older Canadians (and 40% of Canadians in
general) receive the influenza vaccine each The negative consequences of influenza are
year , which is lower than other developed
2
likely underestimated, as it is difficult to
countries such as New Zealand, the United accurately determine the extent and degree
States, and the United Kingdom. What 3
to which influenza affects other health
makes matters worse is that vaccination complications including overall mortality.
rates among older Canadians have also For example, when the cause of death is
stagnated in recent years, and may even be due to a complication, or to an underlying
decreasing, despite the additional risks condition which was worsened by influenza,
posed by COVID-19 and higher reported it is not necessarily understood that this is a
intention to get vaccinated. 4
direct consequence of influenza. Despite its
severity, popular misconceptions regarding
Over the next two decades, Canada’s the seriousness of influenza persist, with
population aged 65 and older is expected many people often dismissing its symptoms
to double. Influenza rates could also climb
5
as being ‘just a cold’.
during this period because those aged 65
and older, as well as those living with Vaccination is overall the best way to
chronic health conditions, are prevent influenza. However, older adults
disproportionately affected by influenza. As and people living with chronic conditions
a result, we expect that serious influenza respond less robustly to vaccination. One of
outcomes will become more prevalent. the most important ways to reduce rates of
Nevertheless, we still do not fully influenza among this population is through
understand the burden of influenza among widespread influenza vaccination or herd
those infected with the virus, even though immunity, which is when enough of the
influenza and its related complications have population is vaccinated, the chance of
a significant impact on the Canadian health becoming infected lowers for everyone.
care system and society in general.
Compounding the problem is that Canadian
In Canada influenza contributes to an health care institutions and providers have
average of 12,200 hospitalizations and an inconsistent and inadequate vaccination
policies and outcomes that contribute to
Executive Summary 05NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
low provider uptake of the vaccination 3. Continue Working Towards Developing
as well. During the 2016-17 ‘flu’ season, only Better Influenza Vaccines
53% of health care providers in hospitals 4. Include Influenza Vaccination in Clinical
were vaccinated against influenza. 9
Guidelines for Older Adults and for
Treating Chronic Conditions
Influenza vaccine therefore faces a policy 5. Provide Clinical Education and Support
and practice mismatch. Both the variable for Primary Care Providers and
effectiveness of the vaccine from year to Pharmacists to Deliver Vaccinations
year and the requirement for an annual 6. Universal Funding for Influenza
vaccination raises unique policy and Vaccinations Needs to Be in Place to
communications challenges for influenza Ensure it is Accessible to All Canadians
compared to other vaccinations. 7. Highly Recommend the Influenza Vaccine
for all Health Care Providers and Mandate
This white paper will provide a concise it for Providers and Residents in
summary of the current scientific Long-Term Care Homes
evidence to inform future policy solutions. 8. Develop Better and Mandatory Reporting
Showcasing these findings will create a of Influenza Vaccination Rates
stronger appreciation for the benefit of 9. Co-administer Influenza with COVID-19
influenza vaccination and other measures Vaccines
in preventing influenza, as well as its
often related but unattributed While Canada recommends
that 80% of older adults
complications including functional loss
and all-cause mortality.
The report makes the following 8
and health care providers
get vaccinated, only
10
evidence-informed recommendations to
support policy and practice approaches
for health authorities and organizations
40% of Canadians
towards supporting both influenza aged 18 years and older 11,
70% of older adults,
prevention and vaccination across Canada: 12
1. Improve Influenza Prevention Practices and approximately
50% of health care
More Generally
2. Promote a Life-Course Vaccination
Schedule that includes Older Adults workers are vaccinated
against influenza.
13
Executive Summary 06NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Background and Context
Why is Influenza an Important Societal Issue?
Each year, influenza epidemics cause 1 billion cases of influenza, 3-5 million cases of
severe influenza-related illnesses, and lead to 250,000 to 500,000 deaths worldwide. 14
Influenza, together with all causes of pneumonia, is the 7th leading cause of death in
Canada, 15 and is the leading cause of death among vaccine-preventable diseases. 16
Top 10 Leading Causes
es
cer uri
inj of Death (2019)
17
C a n s e a l
1 D ise
a
n t ion
e a rt n i nte
2 H s / u a s es
i d ent D ise
Acc t ory
3 e s pir
a
o k R e
Str e r
4 i c Low
h r on
5 C o nia
e t es n e um
b P
6 Dia and
e n za ase
l u s e
Inf ’ s di
7 e i me
r
h
Alz
8 e
u i cid a se
S e
9 e y dis
n
10 Kid
Background and Context 07NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
In Canada
Influenza cases peak during our November
to March ‘flu’ season. 18
Influenza has been reported to cause an average
of 12,200 hospitalizations annually. 19
Influenza has been reported to cause an average
of 3,500 influenza-related deaths annually. 20
Although most Canadians do not perceive always tested for influenza when seeking
influenza as a serious threat, (perhaps medical attention. In addition, people
because most ‘flu’ cases experienced are who do seek medical attention may do
mild ), it can lead to severe illness resulting
21
so specifically for a secondary complication
in hospitalization or death and can be or an exacerbation of a pre-existing
particularly hazardous to young children condition, and these visits may never be
and adults aged 65 years and older. 22 This is attributed to influenza, despite its role in
because these populations are at an the complication. 26 Influenza also has a serious
increased risk of secondary complications economic impact on work productivity, 27
such as pneumonia. 23 Older adults, in leading to an estimated
particular, are at increased risk due to the 1.5 million lost work days each year. 28
potential worsening of their underlying
chronic medical conditions. 24
Influenza also has a
The burden of influenza is also a challenge serious economic impact
on work productivity, 27
to assess because its related complications
and exacerbating effects are often not
linked to the original influenza or leading to an estimated
1.5 million lost work days
influenza-like illness. 25 Furthermore, it is
difficult to determine whether mortality is
related to influenza because people are not
each year. 28
Background and Context 08NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Respiratory infections(including Respiratory infections
influenza, colds, and other
(including influenza, colds,
and other respiratory
respiratory infections) have the infections) have the
second-highest indirect
second-highest indirect costs in costs in Canada totalling
Canada totalling $2.8 billion in $2.8 billion in 2008 alone. 29
2008 alone.
29
What is Influenza?
How Does it Work? Influenza, or the ‘flu’, is caused by two
types of constantly mutating viruses – influenza A
and influenza B, 30 and typically infects the nose,
throat, and lungs. 31 It is most contagious when you
have symptoms such as sneezing, coughing, or
anything that may send the virus into the air. It is 39.5º
thought that the ‘flu’ can also be spread if people
touch doorknobs, phones, remotes, or someone else’s
hands who has influenza. 32
The influenza virus is able to mutate, or change, very
quickly – which is why there are constantly new
strains that emerge throughout the influenza season. 33
Some of the symptoms of influenza include a fever of
over 38°C, achy muscles, chills and/or sweats,
headache, dry and persistent cough, fatigue/weakness,
nasal congestion, and a sore throat. 34
Background and Context 09NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Populations at Higher-Risk for Influenza
Canada’s National Advisory Committee on Immunization (NACI) and Public Health Ontario
(PHO) consider those living with chronic conditions to be at increased risk of
influenza-related complications including hospitalizations and death.
Those living with the following
chronic conditions are considered
at increased risk Heart or lung conditions (including asthma and
chronic obstructive pulmonary disorder)
Diabetes
Conditions that compromise the immune
system, especially cancer
Kidney disease
Dementia
History of stroke
Blood disorders
Neurologic and neurodevelopmental conditions
Morbid obesity (Body Mass Index (BMI)>40). 35, 36
Other groups at increased risk for
complications of influenza37 People aged 65 years and older
Children under 5
Pregnant women
Indigenous individuals
Long-term care residents
Background and Context 10NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
In Ontario, over 65% respiratory conditions including pneumonia
and influenza, other acute respiratory
of those who had a diseases, and chronic lung diseases. 44
reported direct influenza People living with diabetes are also
complication had one or considered to be at increased risk for
more underlying medical
influenza-related complications. 45 People
living with diabetes have been found to be
risk factors. 38 more likely to be hospitalized and die. 46
Diabetes may weaken the immune system
In Ontario, over 65% of those who had a and make it harder to fight off infections,
reported direct influenza complication had while it may also make it harder to control
one or more underlying medical risk blood sugar. 47
factors. 38 Research has found that patients
living with cardiovascular disease have an Chronic lung diseases, neuromuscular
increased risk of adverse events from diseases, neurological diseases, cancer and
influenza infection including pneumonia, chronic kidney diseases are also associated
heart attacks, hospitalizations, and with an increased risk of death from
death. 39,40,41 A 2018 study suggested that influenza. 48 Those with chronic lung
hospital admissions for heart attacks were diseases and chronic obstructive pulmonary
six times higher a week after laboratory disease, who also have influenza,
confirmed influenza when compared to experience increased risk of death, hospital
controls. 41a It was also higher after infection admission and admission to an intensive
with other respiratory viruses. 41b It is further care unit, respectively. 49
thought that some of the costs associated
with treating heart disease in general may A Disproportionate Influenza Burden for
be due to the increased hospitalizations those aged 65 years and older
due to cardiovascular complications that
occur during the influenza season. 42 In Canada, the prevalence of high-risk
medical conditions for influenza
Obesity, defined as having a Body Mass complications (i.e. heart disease, lung
Index (BMI) over 30, has been found to be diseases, diabetes, cancer, or kidney
associated with an increased risk of diseases) ii, increases dramatically with age.
complications due to influenza including In Ontario, for those aged 20-64,
respiratory-related hospitalizations. 43 The approximately 30% have one of these
association was most strongly related to medical conditions, this rises to
ii
Based on NACI recommendations
Background and Context 11NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
approximately 53% of those over age 50, lead to influenza complications. Adults
and to over 70% among those over aged 65 aged 65 years and older accounted for
and older. 50 about 18% of Canada’s population and 21%
of Canada’s laboratory confirmed cases for
The presence of chronic conditions influenza A and influenza B infections
increases the likelihood of complications during the 2019-20 influenza season. Yet
from influenza, including increased older Canadians accounted for the clear
hospitalizations and higher mortality majority of Canada’s influenza-related
rates. 56 For those who were hospitalized deaths, with 70% of all reported influenza
with influenza in Ontario, over 65% had an deaths during the 2019-20 influenza season
underlying condition; while approximately occurring among those aged 65 years and
85% of those who died from complications, older. 57a
had underlying risk factors. 57
The highest rates of complications have
Older adults bear the greatest burden of been reported in those aged 70 and older
influenza due to having a higher prevalence with an underlying condition. 58
of high-risk medical conditions that can
Why Are Older Adults Particularly
Vulnerable to Influenza? Introducing
the Concept of Immunosenescence. Older adults naturally have diminished
immune system functioning as they age, and are more likely to
contract influenza and less likely to respond well to the vaccine. 51
Immunosenescence refers to changes that occur in the immune
system as people age, which results in an increased risk of infectious
disease and decreased protection from vaccination. 52 There have
been attempts to better address the lack of effectiveness in adults
aged 65 years and older including using new vaccines that have
been developed to address the changes in immune function. 53
Another way to increase protection for individuals aged 65 years
and older, is indirectly through herd immunity (i.e. vaccinating
those around them). 54
Background and Context 12NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
For those who were decline can occur very quickly during a
hospital stay. 59 Studies have found that as
hospitalized with many as one-third of older adults leave
influenza in Ontario,
hospitals with a reduced ability to carry out
their activities of daily living. 60
over 65% had an
Indeed, it has been shown that prolonged
underlying condition; stays in hospitals can lead to a ‘cascade of
while approximately 85% dependency’ where immobility leads to
poor outcomes including significant
of those who died from functional loss that in some cases requires
complications, had older patients to have additional
rehabilitative care or to move to a long-term
underlying risk factors. 57 care home. 61 The decline of independence
and functional ability among older patients
Influenza increases the risk of while in hospital can be exacerbated
hospitalization among older adults, which by influenza. It has been found that
can be devastating for their health. Any influenza can impact a person’s ability to
hospitalization (due to ‘flu’ or in general) perform their activities of daily living,
can severely affect an older adult’s ability to as well as cause weight loss, pressure ulcers,
live independently because functional and infections. 62
100
Figure 1: Prevalence of selected medical conditions by age55
90
PERCENT WITH MEDICAL CONDITION
80
70
60
50
40
30
20
10
0
20-29 30-39 40-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+
AGE GROUPS
Diabetes COPD Asthma At least one cardiovascular condition
Immunocompromised At least one high-risk condition
Background and Context 13NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Vaccination –
A Public Health
Success Story
Some of the challenges of improving It is because of how well vaccines work that
influenza vaccination rates may ironically be people have forgotten how severe many
due to the public health success of once common diseases were. This is
vaccinations in general. Vaccines have been especially true for diseases that have been
estimated to prevent 2-3 million deaths entirely or almost completely eradicated.
annually worldwide. 63 However, more frequent travel of people
around the world means that some of these
Vaccines have been diseases that were once eradicated may
estimated to prevent make their way back into Canada as they
are just a ‘plane ride away’ (e.g. polio). 64
2-3 million deaths
annually worldwide. 63
Eradicating Smallpox
through Vaccination Smallpox was an infectious disease that
caused painful, red blisters, with
epidemics killing millions of people worldwide, including
over 3,000 Canadians annually. 65 The smallpox vaccine
was the first that was widely used and smallpox became
the first human infectious disease to be eradicated, back
in 1979. 66 Smallpox was easier to target because it had
very distinct clinical features that were well recognized
and feared. 67 Smallpox remains the only human infection
to ever be eradicated. 68
Vaccination – A Public Health Success Story 14NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population How do Vaccines Work? In general, vaccines use a tiny amount of This occurs when there are enough people dead or weakened virus/bacteria or toxin. in the community immunized against a This helps the body to build ‘antibodies’ disease that there is an overall decrease in which are like memories in the immune the risk of the disease for everyone. 74 system. 69,70 Vaccines do not cause the Vaccination protects you from getting sick if disease itself, because the virus they use is you are exposed to the influenza virus, too weak to cause harm, but strong enough which then protects others because you are that the immune system’s reaction to it will less likely to spread the virus. 75 help it protect against infection later. 71 Humans naturally form immunity when Herd immunity is particularly important as infected with influenza, but because the it protects vulnerable groups who cannot virus changes rapidly, previous infection is yet be immunized, such as infants (who usually not effective in preventing or cannot be immunized before 6 months of lessening the severity of influenza in the age), cancer patients undergoing future. 72 There are some vaccines chemotherapy, the older adults who are that protect against one disease with a more likely to experience single injection (i.e. influenza vaccine) and immunosenescence, and other people who there are some vaccines that cover multiple cannot be immunized for medical reasons. 76 diseases with a single injection (i.e. measles, mumps, and rubella). 73 Herd Immunity Vaccines are not only a protection mechanism for an individual, but they can also help an entire population through ‘herd immunity’ or ‘community immunity’. Vaccination – A Public Health Success Story 15
NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
The Influenza
Vaccination – Still Our
Best Defence Against Vaccination is the best defence against
Influenza
influenza. 83 Public health agencies all over
the world recommend influenza vaccination
as a key defence against the ‘flu’. The World
Health Organization (WHO) recommends
Vaccination is the best that pregnant women, children aged 6-23
defence against months old, older adults and people living
with chronic conditions should be priority
influenza. 83 groups for vaccination. 84
How does the Influenza Vaccine
get to the Providers in Canada?
First, the World Health Organization
( WHO) determines which virus is most likely to cause
infection in the upcoming season. 77 Then the WHO distributes
the strains and reagents to the influenza vaccine
manufacturers and continuously monitors the quality of the
vaccine that is produced for distribution. 78
Influenza vaccine manufacturers across North America and
Europe participate in safety checks and processes before
their vaccines are distributed. 79 The Government of Canada
purchases influenza vaccines for the provinces and territories
through Public Works and Government Service Canada. 80
The Public Health Agency of Canada (PHAC) helps coordinate
the distribution of the vaccines and works with a Federal/
Provincial/Territorial (FPT ) committee to address vaccine
supply issues. 81 PHAC carries out surveillance for any adverse
effects from the vaccine. 82
The Influenza Vaccination – Still Our Best Defence Against Influenza 16NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
It also recommends that health care Why Do We Need to Get a ’Flu Shot’
providers (HCPs) be vaccinated as they are Every Year?
potential sources of influenza infection 85
and are more likely to be in contact with The influenza vaccine differs from other
individuals at higher risk, such as infants, vaccinations because the circulating viruses
older people and people living with mutate each season (and throughout the
chronic conditions. HCPs and people who season). This means that every year a new
live with children also have an increased vaccine is created for the upcoming
risk of contracting influenza. 86 HCPs may influenza season. 88 The effectiveness of the
develop asymptomatic or very mildly influenza vaccine depends on how well the
symptomatic infections, which is World Health Organization selecting the
particularly problematic because they may vaccine strains predicts what viruses will be
not appear sick, but are still able to pass it present that season, and how much the
to the vulnerable people (i.e. frail elderly) influenza viruses mutate in the six months it
they care for. 87 takes to make influenza vaccines. Overall,
influenza vaccine effectiveness is about 60%
in healthy adults. 89 However, it varies
substantially from year to year, and
differs for different strains. For example,
vaccine effectiveness varied from 10% to
60% between the 2004-05 and 2016-17
seasons. During the 2019-20 season, the
overall estimated effectiveness of the
influenza vaccine was 53%. 90
In addition, the effectiveness of the vaccine
wanes over time. It has been found that as
the time since the influenza vaccine was
administered increases, the effectiveness of
the vaccine decreases. 91
The Influenza Vaccination – Still Our Best Defence Against Influenza 17NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
How the Influenza
Vaccine Works
Influenza viruses are covered by proteins
called ‘hemagglutinins’, which have a head and a stalk portion.
If the head of the hemagglutinin locks onto a human cell, it
can enable the influenza virus to spread by replicating itself.
The influenza vaccine uses a dead or weakened version of the
flu virus to get the immune system to produce antibodies,
which are Y-shaped molecules. 92 Antibodies bind to the head
of the hemagglutinin, which then stops it from being able to
infect our cells. 93 It is the head of the hemagglutinin that
changes every year and this is what we have to vaccinate
against. 94 This means that the antibodies that our body made
last year after receiving the influenza vaccine (or being
infected by influenza) may no longer be effective, and this can
cause us to still be susceptible to getting sick from
this year’s upcoming strains of influenza. 95
The flu virus is a sphere covered
by numerous proteins know as
hemagglutinin, which resembles
a lollipop.
96
The flu shot prompts our bodies to
make antibodies, which block the
hemagglutinin head from locking into
our cells, preventing illness.
The Influenza Vaccination – Still Our Best Defence Against Influenza 18NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
What are the Different Types of
Influenza Vaccines
The Influenza Vaccine - How is it Made? Most influenza vaccinations are made to
protect against three viruses: an influenza A
Each year, extensive research is conducted (H1N1) virus, an influenza A (H3N2) virus,
by scientists to determine which influenza and an influenza B virus. 98 These are called
strains are most likely to occur in the ‘trivalent’ vaccinations. There are also
upcoming influenza season and then the ‘quadrivalent’ influenza vaccinations which
vaccine is formulated to protect against are designed to protect against four
those strains. 97 different influenza viruses. 99
Inactivated Influenza Adjuvanted, Inactivated
Vaccines (IIV) In this Influenza Vaccines These vaccines
vaccine, the include an
influenza virus has been killed; adjuvant, which is a substance
there are both trivalent that aims to elicit a stronger
(protects against three strains immune response in the
of influenza) and quadrivalent recipient. 101 This type of vaccine is
(protects against four strains targeted to those aged 65 years
of influenza) versions. 100 and older. 102
High-dose Inactivated Live Attenuated
Influenza Vaccine Influenza Vaccine
The high-dose
influenza vaccine contains the three This vaccine is made from
influenza strains that are predicted weakened influenza viruses
for the upcoming influenza season. 103 and is given through a nasal
The high-dose vaccine contains four spray and is approved for
times the amount of dose of the those aged 2-59. 105
standard-dose influenza vaccine.
This vaccine is being targeted to
those aged 65 years and older.104
The Influenza Vaccination – Still Our Best Defence Against Influenza 19NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
New and
Emerging Findings
• In 2018, NACI conducted a literature review comparing the efficacy and
effectiveness of the high-dose to the adjuvanted influenza vaccine in adults aged
65 years and older. The review had four conclusions: (1) there is good evidence that
the high-dose vaccine offers superior protection compared to a standard dose in
older adults; (2) there is fair evidence that adjuvanted vaccine may be effective
reducing hospitalization for influenza and influenza complications in older adults
compared to the unvaccinated; (3) there is insufficient evidence that the
adjuvanted vaccine is more effective than those who received an unadjuvanted
trivalent inactivated vaccine; and (4) there is no evidence on how the high-dose
vaccine directly compares to the adjuvanted vaccines. 106
• NACI’s 2021 recommendation at the public health program level for adults aged 65
years and older is that any of the available influenza vaccines should be used for
public health programs. However, both the high-dose trivalent and quadrivalent
high-dose vaccines provide greater protection among older adults compared to
their standard dose equivalents. 107
• A recently published study comparing adults aged 65 years and older in the United
States during the 2017-18 and 2018-19 influenza seasons found that the use of
enhanced influenza vaccines, both the high-dose and adjuvanted flu vaccines,
provided a higher and level of protection against influenza related hospitalizations
compared to standard dose influenza vaccines. Furthermore, this study found that
older adults receiving the adjuvanted influenza vaccine had significantly fewer
influenza-related medical encounters compared with individuals receiving the
standard and high-dose influenza vaccines during the 2017–18 and 2018–19
influenza seasons in the United States. 107a
• For the upcoming 2021-22 influenza season, Alberta, New Brunswick, Prince Edward
Island and Yukon will provide high-dose influenza vaccines to all adults aged 65
years and older 109, 109a,109b,109c, while Ontario has purchased and will offer either the
high-dose or adjuvanted influenza vaccines. 108 Some provinces also fund enhanced
influenza vaccines but only for certain groups of older adults, such as British
Columbia and Manitoba, where the high-dose vaccine is offered free of charge to
individuals aged 65 years and older who live in long-term care, assisted living, and
in Indigenous communities. 109d, 109e
The Influenza Vaccination – Still Our Best Defence Against Influenza 20NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Spotlight on Current Research around
the Influenza Vaccine in Canada
INVESTED – INfluenza Vaccine to Effectively vaccine (TIV ), is more effective at reducing
Stop cardio Thoracic Events and death and heart/lung disease-related
Decompensated heart failure Trial 110
hospital admissions.
Influenza can lead to many complications The INVESTED trial is enrolling individuals
and/or death in those living with heart aged 18 and older with at least one heart
disease. It has been found that disease risk factor and a history of a heart
influenza-related death is more common in attack (within the past year) or prior
individuals living with heart disease than hospitalization for heart failure (within the
individuals living with any other chronic past 2 years). The trial will randomly assign
condition. People who have heart disease participants to either receive the standard
who then get influenza are more likely to QIV vaccine (or receive the high-dose TIV
have a heart attack. Those who have heart form of the vaccine or receive the high-dose
failure are more likely to be hospitalized. form of the vaccine. iii This is a high-dose
Vaccination has been shown to reduce the trivalent vaccine that is currently available
risk of major cardiac events. 111
Furthermore, for those aged 65 years and older but is
there is already some evidence to suggest considered investigational for anyone
that the high-dose vaccine can decrease younger than 65.
the likelihood of influenza infection for
individuals living with heart disease. For more details about the INVESTED Trial
please visit http://www.investedtrial.org/.
The INVESTED trial taking place
across the United States and Canada is
looking to determine which of the two
formulations of influenza vaccine, either
the standard quadrivalent influenza vaccine
(QIV ) or the high-dose trivalent influenza
The Influenza Vaccination – Still Our Best Defence Against Influenza 21NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Influenza Vaccination Internationally
Only 59% of WHO member countries
Canada’s influenza reported having a national influenza
immunization policy (as of 2014). 116 Among
vaccination rate iv for those countries that did have a national
older adults aged 65 policy in place, their programs targeted
specific risk groups (as defined by the WHO)
years and older is including pregnant women, young children,
lower than other those living with chronic conditions, older
adults, and health care workers. 117 High or
developed countries upper middle income countries were more
likely to have a national policy. 118 In
Canada’s influenza vaccination rate of addition, these countries were more likely
70% 112
for older adults aged 65 years and to have introduced national policies around
older is in the top third of other developed other vaccines. 119
countries, well above the OECD average of
51%. 113 Canada lags behind Ireland, Greece,
New Zealand, and South Korea. 114 It is
important to note that among OECD
countries, only South Korea has achieved
the World Health Organization's target
vaccination rate of 75% for older adults. 114,115
iv
The OECD Indicator for influenza refers to
vaccination rates among the elderly, defined as the
number of people aged 65 years and older who are
vaccinated against influenza in a given country
The Influenza Vaccination – Still Our Best Defence Against Influenza 22NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Figure 2: Percentage of Population aged 65 years and older who
have Received a Seasonal Influenza Vaccination for OECD Countries115
90
80
70
60
OECD
50 Average
40
30
20
10
0
ia
Re ria
ng c
No ry
Ge ay
m y
Fi rg
d
n
ce
Be y
Po um
er l
Sp s
C in
ite ada
ite Ire s
Ze m
Gr d
ut ece
a
Fr k
d
th ga
nd
e
Hu bli
xe an
l
re
ar
pa
an
an
n
Ita
ak
a
o
a
bu
at
an
rw
t
la
Ne rtu
Ko
nm
Ne ngd
i
ec Aus
e
pu
Lu rm
la
Un an
nl
al
Ja
lg
St
ov
h
De
Sl
d
Ki
w
h
d
So
Cz
Un
This figure was retrieved from https://data.oecd.org/healthcare/influenza-vaccination-rates.htm. The 2019
Canadian influenza vaccination rate for adults aged 65 years and older was 60.2%, extracted from the 2019
Canadian Community Health Survey (CCHS). However, we believe that 70% vaccination rate is a more accurate
estimate of influenza vaccination among adults aged 65 years and older. This figure was taken from the Public
Health Agency of Canada’s 2019-20 influenza vaccination coverage estimates, which can be retrieved from
(https://www.canada.ca/content/dam/hc-sc/documents/services/immunization-vaccines/vaccination-coverage/sea
sonal-influenza-vaccine-coverage-in-canada-en.pdf )
The Influenza Vaccination – Still Our Best Defence Against Influenza 23NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Comparing Influenza Other Means of
and COVID-19 Vaccine Prevention
Uptake among Older
Immunization alone
Adults in Canada is not enough.
COVID-19 has greatly impacted Canadians Immunization alone is not enough. In
of all ages. Canada has recorded almost 3 addition to influenza vaccination, there are
million cases of COVID-19 and nearly 33,000 other important steps that may prevent
deaths since the beginning of the COVID-19 influenza from spreading. These include:
pandemic. Approximately 93% of these
Regular and thorough hand-washing
fatalities have occurred among Canadians
aged 60 years and older. However, Coughing into sleeves
Canadians aged 60 years and older have not
hesitated to get COVID-19 vaccines. 115a Avoiding touching one’s face with
their hands
In fact, Canadians aged 60 years and older Disinfecting commonly touched
have consistently had the highest surfaces (i.e. doorknobs)
vaccination rates in comparison to other
Strengthening one’s immune system
age groups. As of January 2022, 96% of
(i.e. through healthy eating and
Canadians aged 60 years and older have physical activity)
received at least one dose of a COVID-19
vaccine and 94% have received two Avoiding interactions with others who
are feeling ill 120
doses. 115b
All of these measures will help prevent the
Moreover, Canada achieved 90% coverage
spread of not only influenza, but other
in a short period of time—from
infections and illnesses as well.
mid-December 2020 and mid-June 2021—
suggesting that there is the potential to
Antiviral medications can also be used to
achieve high rates of influenza vaccination
control cases of influenza. The Association
among older adults as well. 115c
of Medical Microbiology and Infectious
Disease Canada (AMMI Canada)
recommends that treatment with antivirals
Comparing Influenza and COVID-19 Vaccine Uptake among Older Adults in Canada 24NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
begin as soon as possible after symptoms
occur, with better effects if started within
Vaccination Policies and
12 hours (versus 48 hours). 121 Outcomes in Canada
AMMI also supports the selective use of
antivirals for prophylaxis, for example using The State of Influenza Vaccination
them to protect high-risk groups who Policies and Outcomes in Canada
cannot be vaccinated. 122 The Ministry of
Health and Long-Term Care in Ontario Influenza vaccination is recommended for
recommends that residents of long-term all Canadians aged 6 months of age or
care homes, their families, formal older– with particular recommendations for
caregivers, and visitors be educated on groups that are at higher risk of influenza
vaccination policies and recommendations, complications or hospitalizations (i.e. those
including education in proper hygiene. 123 aged 65 years and older, pregnant women,
There are policies that recommend wearing and those living with chronic conditions). 125
masks to control the spread of influenza –
especially for those who may be infected A total of 11 provinces and territories
asymptomatically and for the protection of provide universal public funding for
those who are unvaccinated. 124 influenza vaccines. 126 While all jurisdictions
provide public coverage for people aged 65
AMMI also supports the selective use of years and older to access influenza vaccines,
antivirals for prophylaxis, for example using Ontario is the only province that provides
them to protect high-risk groups who older adults with publicly funded enhanced
cannot be vaccinated. 122 The Ministry of vaccines in the form of the high-dose
Health and Long-Term Care in Ontario quadrivalent and adjuvanted influenza
recommends that residents of long-term vaccine. 108 Four jurisdictions - Alberta, New
care homes, their families, formal Brunswick, Prince Edward Island, and Yukon
caregivers, and visitors be educated on - offer the high-dose vaccine to their entire
vaccination policies and recommendations, populations aged 65 years and older as part
including education in proper hygiene. 123 of their publicly funded seasonal
influenza vaccine programs. 109,109a,109b,109c
There are policies that recommend wearing In other jurisdictions, only certain groups of
masks to control the spread of influenza – older adults such as residents of long-term
especially for those who may be infected care settings may be eligible for publicly
asymptomatically and for the protection of funded high dose vaccines, as is the case in
those who are unvaccinated. 124 British Columbia and Manitoba. 109d,109e
Other Means of Prevention 25NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
A total of 11 provinces The Ontario program was found to be
cost-effective because it reduced reported
and territories provide influenza cases, and the use of health
universal publicly funded services such as physician visits,
hospitalizations and mortality. 129
influenza vaccines. 126
Canada’s provinces and territories also
The provinces that currently do not provide differ in how they deliver influenza
universal funding for influenza vaccines are vaccination. In general, vaccination is
British Columbia and Quebec. In these offered at doctor’s offices, flu clinics, public
provinces, the influenza vaccine is funded health centres, workplaces, schools,
for people living with certain chronic hospitals, institutions, and pharmacies.
conditions (i.e. cardiovascular disease, Enabling pharmacists to offer influenza
asthma, diabetes) and for those in vaccinations is a relatively new initiative in
long-term care homes. 127 In British Canada, which was designed to improve
Columbia, it is also funded for those aged access and uptake. Alberta and British
65 years and older, while in Quebec is it Columbia introduced this policy for
funded for those aged 75 years and older. pharmacists during the 2009-10 influenza
Quebec no longer recommends the season, New Brunswick in 2010-11, Ontario
influenza vaccine for healthy adults aged 60 in 2012-13, and Nova Scotia in 2013-14. 130
to 74 years, but these persons can also get Pharmacists can now also administer
the vaccine free of charge if they would like influenza vaccines in Manitoba, Prince
to get it. 127a Edward Island, Newfoundland and Labrador,
and Saskatchewan. 131 Pharmacists can now
Ontario was the first province to implement offer the influenza vaccination
a large-scale Universal Influenza in in 11 of Canada’s 13 provinces and
Immunization Program (UIIP), which was territories. 131a
found to be associated with decreased
mortality, hospitalizations, emergency
department use, and doctor’s office visits
Pharmacists can now offer
when compared to other provinces in the influenza vaccination
Canada. 128
in 11 of Canada’s 13
provinces and territories.
Vaccination Policies and Outcomes in Canada 26NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Influenza Vaccination Policies
by Province (2020-21) Influenza vaccines are provided at public health
clinics, physician’s offices, travel clinics, or pharmacies in certain provinces. 120
Province/ Who can administer the Universal
133
Territory influenza vaccination? Funding?
Alberta Alberta Health Services, Yes
family doctors & Alberta also funds high-dose
pharmacists 134 influenza vaccines for all adults
aged 65 years and older
British Public health clinics, No
pharmacies, physician’s
Columbia But, funded for:
offices, and travel clinics 135
Persons with morbid obesity
Indigenous people
Children under 5
Pregnant women
Persons 65 and older
Residents of nursing homes or
chronic care homes
Health care workers
Household contacts of people at
high-risk
Persons with weakened
immune systems
Essential community services (i.e.
first responders)
People living with chronic
conditions such as: cardiac,
pulmonary, diabetes, asthma,
renal, liver, anaemia or
hemoglobinopathy, HIV patients,
immunosuppression and
cancer, neurologic or
neurodevelopmental conditions
British Columbia is now funding
high-dose influenza vaccines for
adults aged 65 years and older
who are living in long-term care
homes.
Vaccination Policies and Outcomes in Canada 27NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Influenza Vaccination Policies
by Province (2020-21) Influenza vaccines are provided at public health
clinics, physician’s offices, travel clinics, or pharmacies in certain provinces. 120
Province/ Who can administer the Universal
133
Territory influenza vaccination? Funding?
Public health offices, Yes
doctor’s offices, Starting in the 2017-18 influenza
Manitoba pharmacies, immunization season, Manitoba is funding the
clinics 136 high-dose influenza vaccine for
people aged 65 years and older
who are in long-term care homes. 137
Seasonal influenza Yes
New vaccine will be provided New Brunswick funds the
Brunswick in New Brunswick high-dose influenza vaccine for
through: primary care all adults aged 65 years and older.
providers, Public Health
nurses, New Brunswick
Extramural Program
health professionals and
pharmacists 138
Public health, health care, Yes
Newfoundland occupational health services Individuals are able to receive
and Labrador and physician’s offices and their flu shot free of charge from
pharmacies 139 family physicians. If they go to a
pharmacy they may need to pay a
fee for receiving the flu
vaccine. 139a
Northwest Nurses or doctors 140 Yes
Territories
Northwest Territories is now funding
the high-dose vaccine for adults aged
65 years and older who are living in
long-term care homes. 140a
Vaccination Policies and Outcomes in Canada 28NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Influenza Vaccination Policies
by Province (2020-21) Influenza vaccines are provided at public health
clinics, physician’s offices, travel clinics, or pharmacies in certain provinces. 120
Province/ Who can administer the Universal
133
Territory influenza vaccination? Funding?
Nova Scotia
Pharmacies, doctor’s offices, Yes
Public Health clinics, and in
Nova Scotia is now funding the
some workplaces 141
high-dose vaccine for adults aged
65 years and older who are living
in long-term care homes. 141a
Community Health Centres
Nunavut Yes
or Iqaluit Public Health 142
Ontario Pharmacies, doctor’s Yes
offices, public health units, Starting in the 2018-19 influenza
workplaces, long-term care season, Ontario began funding
homes, hospitals, and the high-dose influenza vaccine
community health centers 143 for adults aged 65 years and
older. Ontario now offers either
the high-dose or adjuvanted
influenza vaccines to adults aged
65 years and older. 144
Both the high-dose and
adjuvanted influenza vaccines are
made available through primary
care providers, participating
pharmacies and retirement
homes, long-term care homes and
hospitals. 144a
Prince Flu vaccination clinics,
Edward Island pharmacists, family Yes
physicians, or nurse PEI is now funding the high-dose
practitioners 145 vaccine for all adults aged 65
years and older. 145a
Vaccination Policies and Outcomes in Canada 29NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Influenza Vaccination Policies
by Province (2020-21) Influenza vaccines are provided at public health
clinics, physician’s offices, travel clinics, or pharmacies in certain provinces. 120
Province/ Who can administer the Universal
133
Territory influenza vaccination? Funding?
Integrated health and No
Quebec social service centre But, funded for:
update where vaccinations Persons with morbid obesity
will be offered 146
Pregnant women
Pharmacists can also People aged 75 years and older
administer influenza Residents of nursing homes or
vaccines. chronic care facilities
Health care workers
Household contacts of people
at high-risk
People living with chronic
conditions such as: cardiac,
pulmonary, diabetes,
renal, liver, anemia or
hemoglobinopathy, HIV patients,
immunosuppression, cancer, and
nueurological or
neurodevelopmental conditions
The vaccine is no longer
recommended for healthy adults
aged 60-74 or healthy children 6-23
months - however, they can receive
the vaccine free if they wish.
Yes
Saskatchewan Public health clinics,
Saskatchewan is now funding the
pharmacies, physician’s
and nurse practitioner’s high-dose vaccine for adults aged
offices 147 65 years and older in long-term
care homes. 147a
Yukon Community health centres Yes
and pharmacies 148 Yukon is now funding the
high-dose vaccine for all adults
aged 65 years and older. 109c
Vaccination Policies and Outcomes in Canada 30NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Research has care settings, influenza vaccination should
be part of patient care plans. 154
found that Furthermore, when transferring patients,
in provinces
information about their vaccinations should
also be provided to the institution they are
where pharmacists are being sent to. 155
able to administer the The Ministry of Health and Long-Term Care
influenza vaccine, more (MOHLTC) in Ontario supports the use of
influenza vaccines as its main preventive
people are vaccinated. 149
measure against influenza in long-term care
homes (LTCHs) and recommends that
all LTCH residents should be vaccinated. 156
Research has found that in provinces where
A study found an almost 20% reduction
pharmacists are able to administer the
in outbreaks in LTCHs when over 90% of
influenza vaccine, more people are
residents were vaccinated versus homes
vaccinated. 149 Pharmacists have successfully
where fewer than 70% of residents were
increased access to the vaccine as they are
vaccinated. 157 The MOHLTC also
conveniently located and accessible to
recommends influenza vaccination for
many individuals, and are more likely to
all visitors to LTCHs. 158
have longer hours, not require an
In 2012, health authorities in British
appointment, and have shorter wait
Columbia were the first to implement a
times. 150,151,152 The pharmacy option may be
“vaccine-or-mask” policy. 159 This policy
especially effective among those in some
requires all employees of the health
high-risk populations who may be averse to
authorities, students, physicians, residents,
visiting doctor’s offices and prefer to visit
contractors, vendors, and volunteers to be
pharmacies, such as smokers. 153
immunized or to be masked during
influenza season. 160 This policy has further
Influenza Vaccination Policies for
been expanded to include all visitors in
Residents/Patients in Institutions
health care facilities. 161 All staff must report
through an online reporting system
The Public Health Agency of Canada
whether they have been vaccinated. 162
recommends that in acute and long-term
Vaccination Policies and Outcomes in Canada 31NIA White Paper: The Underappreciated Burden of Influenza Among Canada’s Older Population
Vaccination Rates Among Canada’s 10
in Canada provinces, Nova Scotia
Current Influenza Vaccination Rates in
consistently achieves the
Canada – Not Up to Our Own Standards highest overall
vaccination coverage -
Only 40% of Canadians with increases from
aged 18 years and older 47% during the
were vaccinated against 2014-15 flu season to
163
influenza. 49% in 2018-19. 166
Only 40% of Canadians aged 18 and older
There is considerable variation in influenza
were vaccinated against influenza during
vaccination rates across Canada. Among
the 2020-21 season, 154 a significant
Canada’s 10 provinces, Nova Scotia
improvement from 29% in 2013, 163a
consistently achieves the highest influenza
but significantly lower than the Canadian
vaccination coverage–reaching 49% of the
government target of 80%. In addition,
its population aged 12 and older in
these most recent rates show that
2018-19. 166 Prince Edward Island and New
influenza vaccinations have actually
Brunswick also had relatively high influenza
decreased during the COVID-19
vaccination coverage above 40% in
pandemic, down from 42% during the
2018-19. 167 Quebec consistently has the
2018-19 and 2019-20 seasons. 154
lowest coverage, decreasing from 26% in
2015-16 to 21% in 2018-19. 168
Vaccination rates in key at-risk groups
Newfoundland, Manitoba, Saskatchewan,
such as older adults (70%) and people
Alberta, and British Columbia all had
aged 18-64 living with one or more
influenza coverage rates between 34% and
chronic conditions (41%) are higher than
39%. 169 Historically, coverage was further
the average among the general
found to be much higher in provinces that
population. 154 However, declining
have universal funding provisions. 170
vaccination rates among older adults in
every province except Newfoundland and
Labrador is a worrying trend. 165
Vaccination Rates in Canada 32You can also read
