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The Flu or Influenza

What is the flu and what causes it?

The flu, also called influenza, is a contagious respiratory illness caused by a virus. When a flu-infected person sneezes, coughs or even speaks, the virus spreads through the air and can infect others who are nearby. The virus usually strikes during the winter.

What are its symptoms?

Although the flu is a respiratory illness, the whole body suffers. Usually, the subject presents acute symptoms that appear suddenly: fever sets in rapidly and is accompanied by chills, generalized weakness, loss of appetite and severe muscular aches throughout the body. The flu rarely lasts more than a few days and most people recover in less than a week without developing complications. Gastrointestinal symptoms like nausea, vomiting and diarrhea can also occur.

Who can catch the flu?

Anyone can catch the flu, especially when it reaches epidemic proportions. When this occurs, the virus may affect 20 to 30 percent of the population.

Because the flu is a serious disease, seniors over the age of 65 and younger people suffering from a latent chronic illness are more likely to catch the flu and develop its complications. In the medical community, these people are referred to as "high-risk" cases.

The following are said to be at "high-risk": Individuals over the age of 60 or suffering from:

a chronic respiratory illness like asthma or emphysema
heart disease
diabetes or a chronic metabolic disorder
anemia or hemoglobinopathy
an illness, or undergoing a treatment that affects the immune system: (HIV carriers, immunosuppression, cancer).

Can the flu be prevented?

Getting a flu shot every fall affords protection against the disease. The vaccine causes the organism to produce the antibodies it needs to defend itself during the five to six-month-long flu season. An annual flu shot wards off the flu in 75 percent of cases; in the remaining instances, it reduces the severity of the illness and can even save lives.

Who should be vaccinated against the flu?

Because the flu claims the lives of over six thousand Canadians each year, and because the influenza virus strains vary from year to year, it is recommended that high-risk individuals take the appropriate vaccine each year.

The vaccine is also recommended for people who live in retirement homes or long-term care units, workers who come into contact with high-risk individuals like police officers, firemen and healthcare providers, and any person wishing to avoid contracting the flu.

Who should not get a flu shot?

The vaccine should not be administered:

to anyone who is allergic to eggs or products containing eggs, as it may contain minute quantities of egg-specific protein capable of causing adverse reactions
to individuals who have reacted to previous flu shots
to anyone having previously shown symptoms of Guillain-Barre syndrome.

If you are running a fever or if you are seriously ill at vaccination time, you should wait until you are fully recovered before taking your flu shot. Ask your doctor whether or not you have to postpone your vaccination.

Does vaccination involve any risks?

Nowadays, flu shots are practically harmless and most people hardly ever have a reaction. One out of four people may experience minor pain at the injection site while even fewer people, and mostly children rather than adults, may develop a bit of fever within 24 hours. Occasionally, the vaccine may cause chills, headaches or slight nausea the day after the shot.

How does the vaccine work?

The inactivated flu vaccine (whose viruses have been destroyed) is updated each year because the viruses change frequently.

The protection appears approximately two weeks after vaccination and covers the entire period during which the virus flourishes. A few vaccinated individuals can still catch the flu, but their symptoms will be more moderate than those of the non-vaccinated.

What kind of treatment is available for the flu?

There is no treatment per se for the flu. In simple cases, doctors usually recommend bed rest as long as the symptoms are severe, and often for one or two days after the fever has broken. It is wise to drink a lot of liquids and to take acetylsalicylic acid (like aspirin) or acetaminophen (Tylenol, etc.) to relieve discomfort caused by the flu.

Children and adolescents should avoid taking acetylsalicylic acid, because of the risks associated with Reye's syndrome, a serious yet infrequent disease of the brain and liver. A wiser choice would be acetaminophen. Their physician may also prescribe an antiviral drug administered orally.

The flu shot, a preventive measure

"Vaccination is the best way to prevent the flu or alleviate its symptoms. It has long been recommended for individuals at high risk of becoming seriously ill or even dying". This recommendation is made by the National Advisory Committee on Immunization (NACI), an organization made up of experts in this field and created by Health and Welfare Canada for the purpose of developing a policy on the recommended use of vaccines

The best time to get a flu shot is in October or November.

Antiviral drugs

Antiviral drugs like amantadine, zanamivir and oseltamivir can prevent and treat the infection caused by the flu virus (influenza A or influenza B). However, they are not designed to replace the annual vaccine for people who need it. If you are worried about catching the flu during the two weeks it takes for the vaccine to become effective, your doctor can prescribe an antiviral drug that will also alleviate flu symptoms if administered 24 to 48 hours following onset of the symptoms. Furthermore, it will not hamper the effect of the vaccine administered by injection.

The administration of antiviral drugs is also useful in the following cases:

For people who wish to protect themselves against the flu but cannot take the flu shot because of serious allergies to egg protein
for people who cannot be vaccinated before the flu season is well under way
for people with immune disorders (these people have to take the antiviral drugs orally in addition to getting a flu shot)
for people who have not yet been vaccinated and come into contact with "high-risk" individuals.

For the time being however, these drugs should not be viewed as a substitute for vaccination, which remains the best method of prevention against the flu.

What is the difference between a cold and the flu?

Unlike the symptoms of flu, cold symptoms only affect the upper respiratory tract. On average, an adult will develop one to three colds a year, while children will catch as many as eight per year.

Symptoms	Cold	Flu
Fever	Rare	Usually high (38 to 40^°), appearing suddenly, and lasting 3 or 4 days.
Headaches	Rare	Significant
Generalized muscular aches	Benign	Frequent, sometimes severe
Fatigue and weakness	Mild	Extreme, may last up to 1 month
Loss of appetite	Never	Common
Exhaustion	Never	Rapid and significant
Nasal discharge	Common	Exceptional
Sneezing	Common	Exceptional
Sore throat	Common	Exceptional
Chest pains, coughing	Mild to moderate,slight cough	Common and may become persistent
Complications	Sinus congestion or earache	Bronchitis and pneumonia can be life-threatening
P.S. If these symptoms persist or if other symptoms appear, do not hesitate to consult your doctor.