Influenza (The Flu)

What is influenza?
There are many viruses that pass from person to person. These viruses are even more contagious during the winter months when we spend more time indoors. Some viruses cause the common cold, others cause influenza.

Influenza, or the flu, is an infectious respiratory disease that begins in the nose and throat (see symptoms below).
Occasionally nausea, vomiting and diarrhea may occur in children, but rarely in adults.
Influenza is not the 'stomach flu', which mainly causes abdominal upset and diarrhea with few other symptoms.
Influenza is caused by a highly contagious virus.
Influenza spreads rapidly from person to person - usually by coughing or sneezing.
Influenza viruses change over time to escape the immunity people develop from having influenza in the past.
New vaccines are created to combat the new strains of the virus.
Influenza is rarely a serious disease, but its complications can be severe.
Influenza can incapacitate a person for five to 10 days and could lead to pneumonia or bronchitis.
Occasionally influenza can lead to death from influenza-related pneumonia, or from other influenza related complications such as an aggravation of underlying chronic heart and lung disease.

Influenza symptoms may include:

sudden high fever
headache
loss of appetite
severe muscle aches and pain
extreme fatigue and weakness
chills
dry cough
sweating
sore throat
runny nose
nasal congestion
sneezing.

What is the difference between the common cold, flu and SARS?
All three viruses are spread from contact with someone who already has the illness.

Common Cold Influenza (flu) Severe Acute Respiratory Syndrome (SARS)

Fever is not common. Fever that lasts for 3-4 days. Fever higher than 38°C (100.4°F).

Runny nose, sneezing, nasal congestion and throat irritation, but no chills, muscle aches, headaches or breathing difficulties. Headache, chills and cough which can lead to muscle aches, sneezing, runny nose, watery eyes, loss of appetite, diarrhea is unusual. If symptoms persist or breathing difficulties develop, seek medical attention. Symptoms are similar to flu symptoms, although diarrhea is more common with SARS than with flu. If you have been exposed to someone with SARS, or have travelled in a region where SARS has been detected, seek medical attention immediately. Please call ahead before visiting your doctor's office, health centre, or emergency room.

Symptoms start to improve after 2-3 days. Extreme fatigue may last 2-3 weeks. Some cases progress to severe pneumonia or respiratory failure, which can be fatal.

How can I protect myself and others from influenza?

The most important thing you can do is get a flu shot
Wash your hands frequently
Cover your nose and mouth with a tissue when you cough or sneeze to protect others from your germs.

Who should get the vaccine?

High risk individuals and groups including adults and children with lung disease, people 65 years of age or older, nursing home residents and staff, and anyone with a chronic disease such as diabetes, cancer, kidney disease or HIV, and anyone who has contact with people in these categories.
Adults and children over six months of age can receive the vaccine, and are encouraged to do so.

NOTE:
People who have had a severe anaphylactic (life threatening) allergic reaction to eggs or to a previous dose of the vaccine should not receive the flu shot. Anaphylactic reactions occur within 20 to 30 minutes after the vaccine has been administered.

What will the vaccine do?

The current vaccine is expected to provide good protection against A/Panama - like viruses and influenza A viruses and to also provide some cross protection against A/Fujian, the newest strain.
After vaccination, the body's immune system produces antibodies which then prevent infection, or reduce the likelihood of severe illness should infection occur.

Will the flu shot give me the flu?

You cannot get the flu from the vaccine. There may be mild symptoms of influenza, but the virus in the vaccine is dead, and so it cannot multiply.
People who become ill after receiving their shot may have caught a cold or another virus. It is also possible to catch another strain of influenza not included in the vaccine.

What should I do if I get the flu or develop flu-like symptoms?

If you have been exposed to someone with SARS, or have travelled in a region where SARS has been identified, seek medical attention immediately.
Get plenty of rest
Drink a lot of liquids
Avoid using alcohol and tobacco
Stay home and avoid contact with other people to protect them from catching your illness
Some over-the-counter medications can help relieve the symptoms of flu such as fever, aches and pains.

NOTE:
Do not give ASA (aspirin) to children or teenagers who have flu-like symptoms unless specifically directed to do so by a doctor. The use of aspirin has been strongly linked with the development of Reye's syndrome, a rare disease that affects mainly children or teenagers during a viral illness such as chicken pox or influenza. Reye's syndrome can be fatal.

Antibiotics do not have any effect against a viral illness like the flu.

When should I see a doctor?
Most people recover within one week to 10 days. If symptoms last more than 10 days, or worsen, visit your family doctor or a walk-in clinic. See a doctor if any of the following symptoms are present:

High or prolonged fever
Fast breathing or trouble breathing
Bluish skin colour
Not drinking enough fluids
Changes in mental status such as difficulty waking, irritability, or seizures
Flu-like symptoms that improve but then return with fever and a worse cough
Worsening of underlying chronic medical conditions such as heart disease, lung disease or diabetes

Where can I learn more about influenza?
For more information, visit Health Canada's Flu Website.