4. Seasonal influenza, or ‘the flu’ as it is often called, is an acute viral
infection caused by an influenza virus, mainly affects the respiratory
system.
Seasonal influenza viruses circulate worldwide and can affect anybody
in any age group.
5.
6. Influenza viruses are divided scientifically into three types designated A,
B, and C.
Influenza A viruses are further classified into different subtypes
according to combinations of various virus surface proteins or antigens :
Hemagglutinin (HA) & Neuraminidase (NA) .
7. 7
Influenza A Virus is subtyped by surface
proteins
Hemagglutinin (HA)–18 subtypes
Neuraminidase (NA)–11 subtypes
8. Influenza A is subtyped by surface proteins
Heamagglutinin (HA)
● 18 different types
● help virus enter cells “key in”
● antibody to HA is protective
Neuraminidase (NA)
● 11 different types
● help virus leave cells to infect others “key out”
9. Both HA and NA proteins which are required for the virus to successfully cause an infection.
10.
11.
12. Wild birds are “natural” reservoir for all influenza A subtypes
13. Natural hosts of influenza viruses
Haemagglutinin subtype Neuraminidase subtype
H 1
H 2
H 3
H 4
H 5
H 6
H 7
H 8
H 9
H 10
H 11
H 12
H 13
H 14
H 15
H 16
N 1
N 2
N 3
N 4
N 5
N 6
N 7
N 8
N 9
16. Many different combinations of HA and NA proteins are possible, all of
which have been found in wild birds, which are the natural reservoir
of influenza A viruses.
Among many subtypes of influenza A viruses,only influenza A(H1N1) &
A(H3N2) are currently circulating among humans as seasonal Influenza
strains.
17. The subtypes of influenza A virus demonstrate species specificity and those,
which infect animals do not usually cause infection in humans.
Influenza B viruses are not divided into subtypes, but can be further broken
down into lineages and strains.
Currently circulating influenza B viruses belong to one of two lineages:
B/Yamagata and B/Victoria..
18. Influenza A and influenza B are responsible for most clinical illness,can
cause outbreaks and seasonal influenza epidemics in humans (that
peak during winter in temperate regions).
Due to this reason, relevant strains of influenza A and B viruses are
included in seasonal influenza vaccines.
19. Influenza type C usually causes either a very mild respiratory illness
or no symptoms at all; it does not cause epidemics and does not
have the severe public health impact of influenza types A and B.
20. How influenza virus change?
Type A viruses undergo changes in their surface antigens or proteins
● Minor changes Antigenic drift
● Major changes Antigenic shift
21. Yearly seasonal influenza epidemics occur because of a process called
antigenic drift (due to imperfect manufacturing, in other words genetic
mutations, of progeny viruses in the “cellular factory,” leading to minor or
small changes occur in the HA and/ or NA proteins of circulating strains &
the formation of new stains within the same subtype).
These changes can prevent the antibodies generated by the body’s
immune system, either from past infection or vaccination, from efficiently
neutralizing the virus. In that setting, reinfection with a mutant virus can
occur.
Antigenic Drift
22. How do yearly epidemics occur?
Answer: A process called antigenic DRIFT.
Imperfect “manufacturing” of virus
Small changes in H and N
Partial immunity in population
Incomplete protection; still get sick
Need new flu vaccine every year
H3N2 H3N2
Immune
System: “Do I
know you? You
look vaguely
familiar!”
23. Antigen drift. The error-prone viral copying machinery makes errors while copying
the viral genome. These small errors can result in a small change to the H or N
proteins (in this case, represented by a red asterisk and the altered shape of the H
protein), which can render it invisible to human (host) antibodies.
24.
25.
26. Antigenic drift occurs in both influenza A and influenza B viruses.
Antigenic drift is the reason that 1 or more of the three virus strains in
the vaccine are updated every year based on what’s been circulating
around the world.
This necessitates the creation of a new flu vaccine every year (as the
new virus strains may not be recognized by the body's immune
system).
27. What drives the occurrence of a pandemic?
Answer:
Instead of antigenic DRIFT occurring,
an antigenic…
…happens.
Immune
System: “Oh my
gosh…I don’t
know you at
all!”
H?N?
29. H1N1 H2N2 H3N2
1918: “Spanish Flu” 1957: “Asian Flu” 1968: “Hong Kong Flu”
40-50 million deaths 2-4 million deaths 1 million deaths
Credit: US National Museum of Health and Medicine
Source: WHO
Pandemic influenza in the 20th Century
40. Estimating the burden of seasonal influenza
Influenza is usually self limiting in healthy individuals, with recovery in 3-7 days.
Elderly people, children under 6 months old, pregnant women, and people with
chronic conditions or immunosuppression are at increased risk of
complications.
Seasonal influenza epidemics can cause febrile illnesses that range in severity
from mild to debilitating and can lead in some instances to hospitalization and
even cause death, mainly among high-risk groups.
41. Seasonal influenza is a serious public health problem, it has been estimated
that in developed countries, annual influenza epidemics infect about 10–20%
of the population each season.
Worldwide, annual influenza epidemics are estimated to result in ~1 billion
cases of flu, ~3–5 million cases of severe illness and up to 650,000 deaths
annually.
Seasonal Influenza Deaths More Common Worldwide Than Previously
Thought.
42. The single best way to prevent the flu
is to get vaccinated every year!
55. Is the vaccine that contains 4 viruses preferred over the
vaccine that contains 3 viruses?
Vaccines that contain four strains of influenza virus may eventually
replace 3-virus vaccines.
CDC and other groups do not have a preference for use of the 4-virus
vaccine over the 3-virus vaccine.
57. Every flu season is different, A flu vaccine is needed every season for
two reasons:
1. The body’s immune response from vaccination declines over time, so an
annual vaccine is needed for optimal protection , Even if the strains have
not changed, getting influenza vaccine every year is necessary to maximize
protection.
2. Antigenic drift (Flu viruses are constantly changing),which may occur in
one or more influenza virus strains.
58. Unlike many other vaccinations, the flu vaccine isn’t a one-and-done deal.
Influenza strains change every year as they circulate and genetically mutate,
making the previous year’s vaccine ineffective
The WHO creates a new flu-fighting cocktail every year based on which
strains are circulating globally and predictions of which strains will be most
common in the upcoming flu season.
59. Each year, a new vaccine must be prepared that will be effective against
the expected type of influenza virus.
The trick is to be able to predict which influenza viruses are going to
cause infection and to prepare a vaccine against those viruses .
60. Influenza vaccine development
Currently, 136 national influenza centers in 106 countries conduct year-
round surveillance for influenza viruse and disease activity.
Each year, based on global surveillance data, the World Health
Organization (WHO) recommends the strains that they believe will be
circulating in the upcoming influenza season.
61. Influenza vaccine development
In February, the WHO makes recommendations concerning the virus
strains to be included in vaccine production for the forthcoming winter in
the Northern Hemisphere .
It takes about 6 months for vaccine manufacturers to grow the viruses in
chicken eggs .
Shipments began in August and will continue throughout September and
October until all vaccine is distributed.
62. |
62
Vaccine Manufacturing Time Lines
M A M J J A S O N D J FF M
WHO
(Northern hemisphere)
PRODUCTION
INTERNATIONAL SURVEILLANCE NETWORK
VACCINE MANUFACTURER
MELBOURNE
(Southern hemisphere)
PRODUCTION
Choice of strains Vaccine on time
63.
64. Experts develop the flu shot through months of research and with an
educated opinion.
Yes, the flu shot only covers you against certain strains. However, the
strains are chosen based on research and data – it’s not just a guess.
Even when the virus in the flu shot is not closely matched to the seasonal
flu virus, the vaccine can still protect many people and prevent flu-related
complications.
65. This protection is possible because the antibodies made in response
to the flu shot can provide some protection against different but
related flu viruses (cross protection).
Plus, it’s better to be covered against some of the possible strains
than none at all.
66.
67. Myth #: You don’t need a flu shot this year if you got one last year
Flu viruses are constantly changing. So vaccines are reviewed every
year and updated as needed.
Last season’s vaccine was developed to fight last year’s virus, but
probably wouldn’t be effective this season. That’s why it’s important to
get this year’s flu shot to fight this year’s virus.
68. If you’ve already had the flu and think you’re immune to another
bout, think again?
Every year, there are two or three strains of the flu making their way
around, so chances are, you could catch the bug again.
If you get your flu shot, you’ll be better protected from what’s out there.
83. |
83
Seasonal Occurrence of Influenza
J F M A M J J A S O N D
Southern hemisphere Tropical Northern hemisphere
The peak of influenza attacks occurs between October and May in the Northern
Hemisphere and between April and September in the Southern Hemisphere.
87. 87
In general vaccination before December is best since this timing
ensures that protective antibodies are in place before flu activity
is typically at its highest.
However, flu season can last as late as May so getting vaccinated
later throughout the flu season, even in January or later, could still
provide protective benefit.
90. The effectiveness of influenza vaccine depends primarily on:
1 . The age and health status of the person getting the vaccine .
2 . The similarity or "match" between the viruses in the vaccine and
those in circulation
Vaccine effectiveness is not 100%, and some people can still
get the flu after being vaccinated.
91. 91
Does the Flu Vaccine Work?
YES!
Studies have shown that flu vaccine is
70-90% effective
in healthy adults
less than 65 years of age.
92. 92
Adults < 65 years
• 70-90% protection against influenza
Adults > 65 years
• 30 - 40% effective among frail elderly persons
• 50-60% effective in preventing hospitalization
• 80% effective in preventing death
93. 93
During seasons when most circulating influenza viruses are
similar to the viruses in the influenza vaccine, the vaccine can
reduce the risk of illness caused by influenza virus infection by
about 50-60% among the overall population.
94. Remember that even when the viruses are not closely matched, the
vaccine can still protect many people and prevent flu-related
complications.
Such protection is possible because antibodies made in response to
the vaccine can provide some protection (called cross-protection)
against different, but related strains of influenza viruses .
95. Even though circulating influenza viruses may “drift or change from
the time the vaccine composition is recommended, the vaccine may
cross-protect against circulating viruses.
The mismatch may result in reduced effectiveness against the
variant viruses, but it still can provide some protection.
96. Seasonal influenza vaccine provides the best protection available
from seasonal flu –even when the vaccine does not closely match
circulating flu strains, and even when the person getting the vaccine
has a weakened immune system.
Vaccination can lessen illness severity and is particularly important
for people at high risk for serious flu-related complications .
97. 97
Vaccine Storage
Store vaccine between 2º and 8º C at all times.
Vaccine should be placed on the middle shelves of the refrigerator
Influenza vaccine should never be exposed to freezing temperature!.
The vaccine effectiveness can be decreased by exposure to light
98. 98
Note: Influenza Vaccine must not be frozen.
It should never come into direct contact with ice.
Transporting Vaccine
Use insulated containers with a temperature monitoring
device and appropriate cooling agents
Keep vaccine in insulated bags – do not carry it in your pocket!
99. 99
90° Angle
Dermis
Fatty tissue
(subQ)
Muscle tissue
Trivalent Inactivated Influenza Vaccine is Administered by
the Intramuscular Route
Needle length & Site depend on:
Muscle size, Fatty tissue thickness,
Vaccine volume, Injection technique
Aspiration is NOT required
103. Used for about up to 1 year depending
on muscle development
Child/BabyInjectionSite
104. Vaccinating Children
Because we are at very public sites, we DO not vaccinate
children who are crying excessively, thrashing, running away or
have to be “held down.” They will have to go to their clinic.
107. 107
.
For adults and older children, the recommended
site of vaccination is the deltoid muscle.
The preferred site for infants (< 12 months old )
and young children (older than 12 months of
age with inadequate deltoid muscle mass) is the
anterolateral aspect of the thigh.
108. Proper placement of a vaccination on an adult patient is 2 - 3 fingers below the
acromion process at the level of the arm pit.
Injection Site
113. Adult Injection Sites
Placement is extremely important and if incorrectly done it can
result in serious harm.
Only use deltoid site – NEVER the buttocks at public clinics
Adults must be seated to vaccinate – NO standing!
114. 114
Shake vaccine vial before withdrawing a dose
Discard vaccine if it contains particulates, appears discolored
Do not administer into buttock muscle because of potential for
injection-associated injury to sciatic nerve
ACIP states that aspiration (i.e., pulling back on the syringe plunger
after needle insertion and before injection) is not required because
large blood vessels are not present at recommended IM injection sites
Do not mix with any other vaccine or solution
Precautions
118. A child requires only 1 dose if they have previously received 2 or more
total doses of any trivalent or quadrivalent influenza vaccine before
July 1, 2018.
The 2 previous doses do not need to have been received during the
same influenza season or consecutive influenza seasons.
Vaccine Dosing Recommendations
119. TIV does not interfere with the effectiveness of other vaccines, it can be
given at the same time or at any time before or after administration of
other inactivated vaccines (e.g. Hepatitis B vaccine) or live attenuated
vaccines (e.g. Measles, mumps and rubella vaccine).
For concomitant parenteral injections, different injection sites and
separate needles and syringes should be used.
Can TIV be administered simultaneously with other vaccines?
120.
121.
122. 122
All people 6 months of age and older should get flu vaccine.
129. Pregnant women, both healthy pregnant women and those with
chronic medical conditions, are at increased risk of influenza
related complications& hospitalization.
The risk increases with length of gestation i.e. it is higher in the
third than in the second trimester.
Seasonal Influenza vaccine &pregnancy
130.
131. Trivalent inactivated Influenza vaccine is considered safe for use
in pregnant women at all stages of pregnancy, in any trimester,
regardless of gestational age
Pregnant women should receive inactivated vaccine (flu shot) but
should NOT receive the live attenuated vaccine (nasal spray).
There is no evidence that influenza vaccine causes any harm to
mother or baby when administered to a pregnant woman
132. Children aged <6 months are not eligible to receive currently
licensed influenza vaccines and should be protected against
influenza through vaccination of their mothers during pregnancy (via
passive transfer of antibodies across the placenta and through
breast milk).
The benefit of vaccination far outweighs any possible risk from the
vaccine itself.. The risk is actually in not getting a flu shot.
135. The trivalent inactivated vaccine (TIV) is also safe for breast
feeding mothers and their babies (via breast milk).
Women who are breast feeding may receive either either inactivated
vaccine or live attenuated vaccine (nasal spray).
136.
137. Health-care workers are an important priority group for influenza
vaccination, not only to protect the individual and maintain health-care
services during influenza epidemics, but also to reduce spread of influenza
to vulnerable patient groups.
Vaccination of HCWs should be considered part of a broader infection
control policy for health-care facilities.
138. Influenza vaccination rates among health care workers still short of
goals
In the absence of contraindications, refusal of HCWs who have direct
patient contact, to be immunized annually against influenza , implies
failure in their duty of care to their patients.”
139. Health care workers should use every opportunity to
give Inactivated seasonal influenza vaccine to individuals at risk of
serious influenza complications,who have not been immunized during
the current season,even after influenza activity has been documented
in the community,
140.
141.
142. Some of my patients refuse influenza vaccination because
they insist they "got the flu" after receiving the injectable vaccine
in the past…What can I tell them?
There are several reasons why this misconception:
1- Less than 1% of people who are vaccinated with the flu shot develop flu-
like symptoms, such as mild fever and muscle aches, after vaccination.
These side effects are not the same as having influenza, but people confuse
the symptoms.
143. 2- Since it takes about two weeks to build protective antibodies after
receiving the flu shot, it is possible for someone to become infected in that
time period or shortly before getting vaccinated.
3- You may be exposed to a to a flu virus not included in the vaccine and
develop illness.
4- Respiratory pathogens that are not related to influenza viruses can cause
“flu-like” symptoms (such as rhinovirus). The influenza vaccine does not
protect you against these pathogens.
144. 5- Unfortunately, some people can remain unprotected from flu despite
getting the vaccine, this is more likely to occur among people that have
weakened immune systems, However, even among people with weakened
immune systems, the flu vaccine can still help prevent influenza
complications.
Protection is never 100%, , especially in older persons and some people can
still get the flu after being vaccinated.
145. Myth #1: I never get the flu so I don’t need to be vaccinated
Just because you’ve been fortunate in the past doesn’t mean you’ll
be so this year.
Remember “Millions of people have never gotten into car accidents.
They still wear seat belts and carry insurance.”
146.
147.
148. Myth #: Flu shot side effects are worse than the flu itself
The most common side effect is discomfort or minor pain around the
site of the injection.
The flu vaccine can occasionally cause side effects such as mild aches,
fatigue, headache, or fever. Because the flu vaccine does not cause the
flu, these symptoms aren’t as severe as those from the flu itself…
Like other injections, a flu shot can cause fainting.
157. Influenza Vaccines and Use of Influenza Antiviral Medications
Administration of inactivated influenza vaccine to persons receiving
influenza antiviral drugs for treatment or chemoprophylaxis is acceptable.
Live-attenuated influenza vaccine (LAIV) should not be administered at
the same time or within 48 hours of cessation of treatment with influenza
antiviral therapy.
158. Influenza Vaccines and Use of Influenza Antiviral Medication
If influenza antiviral medications are administered within 2 weeks after
receipt of live-attenuated influenza vaccine, the vaccine dose should be
repeated 48 or more hours after the last dose of antiviral medication.
159. Though prophylaxis with antiviral agents may be used to prevent
influenza transmission, vaccination is considered the best method
for this purpose.
Influenza vaccination is the primary tool to prevent influenza
infection rather than antiviral chemoprophylaxis
160. Influenza Vaccination for the Hajj and Umrah
The Hajj and Umrah are considered recurrent mass gatherings when
millions of Muslims from all over the world come to the holy places in
Mecca and Madinah in Saudi Arabia.
Infections with influenza viruses are commonly found during these
gatherings.
The SCIPV recommends that pilgrims get vaccinated at least 2 weeks
before performing the Hajj or Umrah (evidence A).
161. The Hajj seasons for the next few years will fall during the months of June
to September.This raises special concern for the Hajj pilgrims arriving
from tropical and subtropical areas, e.g., South and Southeastern Asia,
where influenza positivity rates are higher during June to November
compared with December to May.
Therefore, the SCIPV recommends the administration of the Southern
Hemisphere influenza vaccine prior to the Hajj and Umrah for pilgrims
arriving from the Southern Hemisphere .
162. Furthermore, as the Northern Hemisphere influenza vaccine is not
expected to be available prior to the Hajj in the next seasons for pilgrims
from the Northern Hemisphere,the SCIPV also recommends the
administration of the Southern Hemisphere influenza vaccine to those
pilgrims prior to the Hajj session .
This should receive special attention when the composition of the current
Southern Hemisphere vaccine is based on different characteristics of
circulating influenza viruses utilized for the development of the Northern
Hemisphere vaccine for the previous season.
163.
164. Other Benefits of Influenza Vaccination for Adults with Chronic Health Conditions
165. 165
Is Flu Vaccine Safe?
YES!
Vaccination is the BEST protection
you have against the flu!
166. 166
Immunizations are one of the world's biggest public health success stories,But not all
communities have the same access to vaccines .”
“
