» What is Influenza?
Influenza is a virus, which causes respiratory tract
infections (lungs, throat and nose). There are two types of influenza;
influenza A and influenza B. In young, healthy people, influenza
is not a serious infection, although people with it may feel miserable
for several days. In people over the age of 65 years, and those
with chronic heart or lung disease, it causes more severe symptoms
and may be complicated by congestive heart failure, pneumonia,
or an asthmatic attack. In elderly people with chronic illness,
about 1 in 20 people may need to be admitted to hospital because
of complications of influenza. Approximately 4,000 Canadians die
every year from the complications of influenza.
Influenza season is an 8-12 week period in the winter
that starts sometime between November and February.
» What are the Symptoms
The usual symptoms are fever, chills, sore throat, cough, sneezing,
runny nose, headache, weakness, loss of appetite, and/or muscle
aches and pains. People with influenza can be bedridden for a
week or longer.
» How is it Transmitted?
Influenza is transmitted by droplet spread. When someone who
is infected coughs or sneezes, the virus is released into the
air and falls on anything within about 4 feet. Anyone close to
them can become infected, by breathing in the virus. Depending
on the type of material the virus can live on surfaces or objects
such as tables, water taps, books or clothing for 8-48 hours.
When people touch these objects/surfaces they could pick up the
virus on their hands and infect themselves when they touch their
mouth and nose.
» Who is at Risk?
There are approximately 7 million Canadians who are at increased
risk for serious infection or death from influenza. They are all
individuals with diabetes, HIV, cancer, renal disease, chronic
heart and lung disease, people who are immunosuppressed (including
transplant patients). Children 6 months to 18 years who are being
treated long term with acetylsalicylic acid, all individuals 65
years of age and older and all residents of long term care facilities
(nursing homes, homes for the aged or chronic care facilities)
are also in the high risk groups.
» How can it be Prevented?
Influenza vaccine protects healthy people from getting
influenza 85-90% of the time. In the elderly and those with chronic
illness, influenza vaccine is very effective in preventing death
and other serious complications of influenza, but only prevents
about half of all disease. Influenza vaccine must be given yearly,
and is recommended in Canada for all people 65 years of age and
over, all people with chronic illnesses, and household contacts
and caregivers of such people.
To prevent transmission by contact with contaminated
objects it is important that people cover their mouths when they
cough or sneeze. Frequent handwashing will also decrease transmission.
» How Safe is the Influenza
The influenza vaccine is very safe. The vaccine is
a killed virus and CAN NOT cause influenza. If you become
ill after being vaccinated it is just coincidence and is probably
As with any vaccination, local reactions can occur.
These include mild soreness, redness or swelling at the site.
These may occur in about 1/4 of people who are vaccinated. Fever,
headaches, loss of appetite or nausea, weakness and muscle pains
NOTE: The vaccine is grown in eggs. Therefore anyone
who has had an allergic reaction to eggs should not be vaccinated.
As well, people who are sensitive to thimerisol (a preservative
used in vaccines and in some contact lens solutions) should not
receive the vaccine.
» How do we treat
Since influenza is a virus, antibiotics will not work
to kill it. However, Amantadine is a medication that is very effective
in preventing influenza in people who have been exposed to influenza
A virus. It also reduces the severity of influenza if it is started
within two days of the beginning of illness. It is not effective
if started later. It is not effective against influenza B.
Amantadine is usually given in a dose of 100 mg twice
per day to healthy people, but the dose must be reduced in the
elderly and in people whose kidney function is not normal. It
is available as capsules or as a suspension. It should not be
given to people who are pregnant, people who have seizures, or
people who are taking any of a group of drugs called phenothiazines.
It has few significant side effects, but may cause dizziness,
nausea or difficulty sleeping in about one in twenty people who
» Are there any new
Treatments for Influenza?
A new class of drugs called neurominadase inhibitors
have been developed for treating and preventing infection by influenza
viruses. They work against both influenza A and B. If given to
healthy people within 36 hours of onset of illness, they shorten
the length of time people are ill by about two days. If given
to people who have been exposed to the virus they are very effective
in preventing them from becoming ill and does not have side effects.
This document has been prepared for educational purposes
by Margaret McArthur, RN, CIC
Should you have questions regarding individual health
concerns or health care practices, please consult your physician
or health care provider directly.
This website has been made possible through an unrestricted educational grant from
Pfizer Canada Inc.