Download Press Kit Seasonal Flu

PRESS KIT
SEASONAL INFLUENZA
Sanofi Pasteur – world’s leading influenza vaccine manufacturer
CONTACTS:
Global Media Relations
Alain Bernal
T. +33-(0)4-37-37-50-38
[email protected]
www.sanofipasteur.com
U.S. Media Relations
Marisol Peron
T. +1-570-957-0717
[email protected]
www.sanofipasteur.us
INFLUENZA IS A COMMON BUT POTENTIALLY SEVERE DISEASE
Seasonal influenza is an acute viral infection that spreads easily from person to person and that
circulates year-round worldwide.1,2 Uncomplicated infection is accompanied by the abrupt onset of
fever, sore throat, headache, muscle pain, chills, anorexia, fatigue and severe malaise (feeling
unwell).1,2 Fever lasting 3-5 days, unproductive cough and a runny or stuffy nose are all
common.1,2 Illness usually improves after 1 week, but cough and malaise may persist.2
However, these symptoms are non-specific and can also be caused by other respiratoy tract
infections. As a consequence, influenza is often mistaken for the common cold or other benign
respiratory tract infections; actually, unlike the common cold, flu may cause mild-to-severe illness
and can also induce life-threatening complications, such as viral or secondary bacterial pneumonia
and the aggravation of underlying medical conditions, including congestive heart failure and
diabetes.1,2,3
Influenza illness affects people of all ages, but adults aged 65 or older and children younger than
age 2 are particularly vulnerable, as well as those with certain medical conditions (such as chronic
heart, lung, kidney, liver, blood diseases, diabetes) or illnesses that weaken the immune system.1
Catastrophic disability resulting from influenza-related hospitalizations represents a significant
burden in the elderly population4,5 due to their weaker immune system and to the increased
frequency of chronic conditions in this age-group.6 In addition, more than 90% of deaths
associated with influenza occur in the high-risk groups and in the elderly.1,7,8
In adults, the risk of dying from influenza and related complications increases from the age of 50.9
AS A MAJOR CAUSE OF COMPLICATIONS AND DEATH, INFLUENZA REPRESENTS
A GLOBAL PUBLIC ISSUE
Influenza is a serious public health problem that causes severe illness, hospitalization and death
mainly among high-risk groups (the very young, elderly or chronically ill).1,3 According to WHO’s
estimates, as much as 5 to 15% of the population are affected by upper respiratory tract infections,
in annual influenza epidemics, each year10 (influenza annual global attack rates are estimated
at 5-10% in adults and 20–30% in children8).
Worldwide, annual influenza epidemics result in three to five million cases of severe illness, and
250,000 to 500,000 deaths.1,10
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INFLUENZA IS A HIGHLY CONTAGIOUS ACUTE VIRAL DISEASE11
Influenza is a highly contagious disease that often reaches epidemic proportions. Influenza
epidemics occur yearly during autumn and winter months in temperate regions.1 Influenza viruses
are very infectious and are easily transmitted from person to person through air droplets projected
by coughing and sneezing. The virus can also be spread by shaking hands or touching surfaces
contaminated with the virus.1
The incubation period averages 2 days (range 1-4 days).12
Infected adult individuals are
contagious from the day before symptoms appear until 5 days after onset of the illness,12,13 and
severely immuno-compromised persons can shed the virus for weeks or months.13
Children can be infectious for more than 10 days after the onset of symptoms.13 Day-care and
primary school children often spread the virus into homes and communities,14 as children are
efficient transmitters of influenza viruses. Children 5–9 years of age typically manifest the highest
rates of infection and illness.8
Up to 59% of healthcare workers experience flu infections without classic symptoms and can
transmit the virus to patients.15
INFLUENZA POSES A SIGNIFICANT ECONOMIC BURDEN
Influenza can cause serious economic problems.1
Clinics and hospitals can be overwhelmed
when large numbers of sick people appear for treatment during peak periods of illness.1
In industrialized countries, influenza is associated with a considerable economic burden in terms of
healthcare costs, lost days of work or education, general social disruption and workforce
productivity losses.1,8 Indirect costs of influenza can account for 80–90% of the total costs and
stem largely from work absenteeism, disruption of activities and loss of productivity.16,17
Annual direct costs of influenza, including costs of hospitalizations, outpatient visits and care,
physician visits and drugs, etc. have been estimated at US$ 2.2 billion, and indirect costs
at US$ 8.8 billion in the USA, in 2004.18
In unvaccinated healthy adults aged 50-64 years, influenza illness was shown to be responsible
for 39% of all illness-related work days lost and 49% of all days with illness-related reduced “onthe-job productivity”.19 In the USA, 44 million days of productivity were estimated to be lost due to
influenza illness every year.17
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Estimates from France, Germany and the United States indicate that the total annual cost of
influenza outbreaks varies between US$1 million and US$6 million per 100,000 inhabitants.8
Influenza is the most frequent cause of acute respiratory illness requiring medical intervention
because
it
affects
all
age
groups
and
because
it
can
recur
in
any
individual.11
VACCINATION IS THE MOST EFFECTIVE WAY TO REDUCE THE BURDEN OF
INFLUENZA
To prevent transmission as much as possible, infected people should cover their mouth and nose
with a tissue when coughing or sneezing, and wash their hands regularly.1 Annual vaccination is
however still to date considered as the most effective way to prevent influenza infection and its
complications and to alleviate its economic burden.1 Vaccination is especially important for people
at higher risk of serious influenza complications and for people who live with or care for high risk
individuals.1,2,8
The World Health Organization (WHO) therefore strongly emphasizes the importance of raising
public awareness of influenza and its complications as well as the beneficial effects of influenza
vaccination8 and is working, in close partnership with global health authorities, to strengthen
national and regional influenza diagnostic capacities, disease surveillance and outbreak
responses.1, 20
In 2003, the World Health Assembly urged Member States with influenza vaccination policies to
increase vaccination coverage in all people at high risk, including the elderly and persons with
underlying conditions (with a low-end goal of 75% coverage for the elderly).8,20,21
The approach to influenza control typically aims at reducing severe influenza-related outcomes
largely by vaccination of the elderly, who are at highest risk for influenza-related deaths,22 and,
indeed, among the elderly, the vaccine reduces severe illnesses and complications by up to 60%,
and deaths by 80%.1
Influenza vaccination offers approximately 70-90% protection against clinical disease in healthy
adults aged 18-59, provided there is a good match between the vaccine antigens and circulating
viruses.1,8,23
The benefits of influenza vaccination in this healthy adult group23–including health-
care workers–justify the economic costs involved since vaccination prevents absenteeism and loss
of productivity while reducing illness rates and the burden of disease.23,24
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SAFE AND EFFECTIVE INFLUENZA VACCINES ARE AVAILABLE AND ARE TO BE
ADAPTED EVERY YEAR
Inactivated influenza vaccines have been available and in use for more than 60 years and are safe
and effective.1,8 Sanofi Pasteur’s influenza vaccines contain inactivated split viruses that cannot
cause influenza, but induce an immune response that protects against the disease or
complications from the illness1,8,19,24,25,26
Influenza virus infection induces humoral and cellular immune responses, both elements playing a
role in viral clearance and in the prevention of infection. The protective role of antibodies-elicited
either in the natural course of influenza infection or following vaccination and directed against
haemaglutinin (HA) and neuraminidase (NA) *-has been widely demonstrated.2,8
Seasonal influenza vaccines are formulated every year, based on the WHO seasonal
recommendations and contain the HA and NA antigens of two influenza A virus subtypes (H3N2
and H1N1) and those of one influenza B virus.1,8,21
Flu viruses are, indeed, capable of evading
the body’s immune system by undergoing continuous genetic variation2,11 and may change from
season to season.2 Individuals are susceptible to new strains despite previous infection by other
influenza viruses.11
People may have limited protection against new circulating viruses.8
This is why changes in influenza vaccine strains may be needed from one year to another and why
annual administration of influenza vaccine may be recommended by authorities.2
Influenza epidemics occur yearly during autumn and winter in temperate regions and can seriously
affect all age groups.1,2 In some tropical countries, influenza viruses circulate throughout the year
with one or two peaks during rainy seasons.1 Every year the WHO Global Surveillance Network
analyses thousands of virus samples from around the world and makes predictions about which
seasonal strains will likely threaten human health the most in the next season.1,8
The recommendations for the influenza strains to be used in the composition of seasonal vaccines
are determined twice yearly (in February for the Northern Hemisphere and in September for the
Southern Hemisphere) by the WHO, based on the data reported by collaborating influenza centers
throughout the world. Vaccine manufacturers formulate new influenza vaccines every year
accordingly.1,2,8
Immunogenicity criteria for influenza vaccines are well established (see Appendix 1 for the
European Medicines Agency’s immunogenicity criteria for influenza vaccines).
*
Haemaglutinin (HA) and neuraminidase (NA) are antigenic components of the outer membrane of the virus that can be
recognized by virus-neutralizing-antibodies.
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CURRENT CHALLENGES TO INFLUENZA VACCINATION
INFLUENZA VACCINES ARE UNDERUTILIZED AND INFLUENZA REMAINS AN
UNCONTROLLED INFECTIOUS DISEASE17,20,27,28
Despite the implementation of prophylactic measures and the availability of symptomatic or specific
(antiviral) treatments against influenza, and although the quality, availability and use of inactivated
influenza vaccine have increased substantially, annual epidemics continue to cause substantial
sickness and death worldwide as large numbers of unvaccinated at-risk persons are left vulnerable
to infection and its complications, and influenza continues to be a major global health
problem.2,8,20,29
One of the key challenges in influenza prevention is therefore convincing patients to get
vaccinated. Some of the main reasons for people not to be vaccinated include lack of education
about the real impact of the disease and the necessity to repeat vaccination every year, lack of
physician recommendations and mistaken assumptions on the disease or on the vaccine and a
misunderstanding of the vaccination process.30 Additionally, the current most common mode of
vaccination-intramuscular injection-and the fear or the dislike of needles, may represent a potential
barrier for all adults–whether healthy or at-risk–who are apprehensive of injections and/or
needles30 and may keep them from being vaccinated.20,28,30 Patients not only need to be convinced
of the benefit of being vaccinated, but also reassured about the process of receiving an influenza
vaccination.20,27, 28,30
IMMUNOSENESCENCE – WEAKENED IMMUNITY IN THE ELDERLY
The natural ageing process has a major impact on numerous physiological functions, including
immune function.6 Ageing is associated with a decline in the body’s ability to fight infection and
mount novel immune responses.4,6,8,22,31
This weakening of the immune system with ageing phenomenon is called immunosenescence.22
Changes related to immunosenescence include functional defects and modifications in the
concentrations of immune cell type populations, as well as a more inflammatory state. Although
ageing affects all aspects of immune function, the impact on T-lymphocytes is well documented.2,6
As T-lymphocytes are pivotal to the immune response, the overall function of the immune system
is compromised.6,8
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With a weakened immune system, individuals aged 60 and over become not only more susceptible
to infections and to complications from influenza,4,6,22,23,31 but also less responsive to vaccination
compared with younger adults.2,6,22 Despite this, it is important to note that vaccination is still of
significant health benefit in this population.6 Influenza immunization was, indeed, demonstrated to
be associated with a reduction in the risk of hospitalization for heart disease, cerebrovascular
disease and pneumonia or influenza as well as the risk of death from all causes during influenza
seasons.32
In a 10 month follow-up study conducted in elderly adults, influenza vaccination was proven to be
not only strongly associated with a reduction in lung disease-specific mortality, including
pneumonia and chronic obstructive pulmonary disease (COPD), but also with reducing all-cause
mortality and other major cause-specific mortality, after adjusting for age, sex, and risk status.33
Vaccination against influenza was indeed shown to reduce mortality due to stroke by 65%,
diabetes mellitus by 55% and renal diseases by 60%. These results were even better than those
obtained for mortality associated with pneumonia (53%) and COPD (45%).33 The authors
concluded that the influence of influenza vaccination on reducing mortality might be much more
extensive than stated in previous reports that focused mostly on respiratory diseases.33
While influenza vaccination, by preventing influenza infection and complications including
hospitalization and death, is of great benefit in adults aged 60 and over as well as in patients with
compromised immune systems or chronic conditions,6,23 there remains a significant need for more
effective vaccines for this specific adult populations: enhancing the immune response to
vaccination is expected to reduce the morbidity and mortality associated with influenza.
Approaches aimed at surmounting the weakness of the ageing immune system and developing
age-specific vaccination strategies are extremely important.4,22,31
OTHER FACTORS AFFECTING VACCINE EFFICACY
Improving the antigenic match and achieving better understanding of the virulence factors of
influenza epidemics represent other key challenges of influenza vaccination.
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APPENDIX 1: THE EUROPEAN MEDICINES AGENCY (EMA) IMMUNOGENICITY
CRITERIA FOR INFLUENZA VACCINES
The immunogenicity of an influenza vaccine is determined by measuring the antibodies against the
influenza haemagglutinin in blood samples taken before and after vaccination. This measure is
usually performed by a test called haemagglutination-inhibition (HI) test or by a test called single
radial haemolysis test (SRH).
Three parameters are evaluated:24,34
The seroconversion rate, i.e. the proportion of subjects who acquire or achieve a significant
increase in anti-haemagglutinin antibody titer 21 days after vaccination, i.e. a postvaccination
titer ≥ 40 in subjects with a prevaccination titer < 10,
or a ≥ 4-fold increase in titer after
vaccination in subjects with a prevaccination titer ≥ 10.
EMA requested criteria: Influenza vaccines must provide a seroconversion rate of 40% in adults
18-59 years, and 30% in adults 60 years and over.
The seroprotection rate, i.e. the proportion of subjects achieving a post-vaccination antibody titer
equal or superior to the protective threshold (HI titer ≥ 40).
EMA requested criteria: influenza vaccines must provide a seroprotection rate of 70% in adults
18-59 years, and 60% in adults 60 years and over.
The meanfold increase (MFI) in haemagglutinin antibody titers.
EMA requested criteria: influenza vaccines must provide a >2.5 fold increase in adults 18-59
years, and >2 in adults 60 years and over.
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Updated September 2013
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