1. What is seasonal influenza (flu) ?
Seasonal influenza, commonly called “the flu,” is caused by
influenza viruses, which infect the respiratory tract (i.e.,
the nose, throat, lungs). Unlike many other viral respiratory
infections, such as the common cold, the flu can cause severe
illness and life-threatening complications in many people.
Influenza occurs globally with an annual attack rate estimated
at 5%–10% in adults and 20%–30% in children.
2. How does the flu spread ?
Seasonal influenza spreads easily and can sweep through
schools, nursing homes, businesses or towns. When an infected
person coughs, infected droplets get into the air and another
person can breathe them in and be exposed. The virus can also
be spread by hands contaminated with influenza viruses. To
prevent transmission, people should cover their mouth and nose
with a tissue when coughing, and wash their hands regularly.
Who is at risk ?
All are at risk and that is fact. The risk of contracting is
higher in crowded places. Therefore, individuals at high risk
• School children and college students.
• Office staff especially those in call centers/BPO/IT Sectors
• Hotel/Hospital staff and industrial workers.
• Those traveling frequently by public transport.
4. What are the complications of flu ?
Complications of flu can include bacterial pneumonia, ear
infections, sinus infections, dehydration and worsening of
congestive heart failure, asthma or diabetes. Stomach symptoms
such as vomiting, diarrhea and nausea can also occur but are
more common in children.
5. What are the different types of seasonal flu vaccines
There are two types viz...Injectable and intra-nasal vaccine.
The intra-nasal vaccine is given as spray into the nostrils.
The intra-nasal route of administration helps avoid reactions
and pain associated with injections. It also mimics the way
the virus attacks and therefore offers some unique advantages.
In the USA and Russia, where the intra-nasal vaccine is
available, children obviously like it. Serum Institute of
India is amongst the world’s leading vaccine manufactures has
developed an intra-nasal live vaccine. The recommended viral
strains were obtained from the WHO.
6. Is there any difference in the efficacy of Intranasal
and injectable flu vaccines ?
Yes, certainly. Injectable vaccines protect only at the level
of the blood by producing antibodies. While the intranasal
vaccine offers protection at two levels viz the local level
mucosal immunity (the nasal tract) and the blood by producing
antibodies. Due to this, when the disease virus attacks it
gets neutralized at its points of entry i.e. the nasal tract.
If it does manage to pass the first line of defense, it gets
neutralized in the blood.
If a person is protected with an injectable vaccine and the
virus attacks, then the virus will enter through nose,
initially multiply, infect and then its gets neutralized when
it reaches the blood. The person will be protected overall but
may spread the disease in the initial period.
Several studies have proved that the clinical efficacy of
intranasal vaccine is superior to that of injectable vaccine.
7. When is the best time to get flu
Because flu season vary in length and severity, you may go for
flu vaccine dose as soon as the vaccine is available and
throughout the entire flu season.
8. Why should I get vaccine dose every
The flu viruses are constantly changing .Generally new
influenza virus strains circulate every flu season. Each Year,
before flu season, the most recent circulating viruses are
identified by the World Health Organization [WHO] and included
in a new vaccine formula order to offer the best protection.
9. Can Children be vaccinated against
The vaccine is known to be safe in children from 2 to 17 years
of age and is not licensed for use in children younger than 2.
LAIV has been approved for use in healthy adults and Elderly
also (without a history of egg allergies or asthma).
Issued in the public
Serum Institute of India Pvt. Ltd.,