What is influenza?
Influenza is an infection of the lungs and airways caused by a virus, typically influenza Type A or influenza Type B. In North America, it usually affects people between November and April.
Symptoms include sudden fever, chills, headache, body aches and extreme tiredness. Sore throat and a runny or stuffed nose are also common. Most people get better within a week. However, people with long-term health problems or those with weaker body defenses such as the very young, elderly and those on certain medications, may have serious complications such as pneumonia or worsening of their health condition(s).
How can influenza be prevented?
The best way to avoid influenza is to get immunized every year. A new vaccine is made each year because the influenza virus is always changing. The best time to get the vaccine is between early October and mid November, just before the influenza season starts. It takes two weeks for the vaccine to take effect.
Influenza vaccine is 70 to 90 per cent effective in young, healthy people. When a person’s immune system is weakened, the vaccine is not as effective and doesn’t last as long. However, it can lessen the severity of the illness if a person does become infected. People who are severely allergic to eggs should not get immunized because eggs are used in making the vaccine. In rare cases, a person has had an allergic reaction to some other ingredient in the vaccine.
Talk with a public health nurse or physician about the risks and benefits of immunization.
What are “antiviral” medications?
Antiviral medications can stop or slow down the action of viruses. They can be used to help prevent influenza. They can also help shorten the length of time a person has the illness and lessen its severity. The two most commonly used antiviral medications in Alberta are amantadine (for example, Symmetrel®) and oseltamivir (for example, Tamiflu®).
When are antiviral medications used to PREVENT influenza?
Some people may be at risk of getting serious complications from influenza but cannot be vaccinated, for example, because of an allergy to eggs. A doctor may prescribe an antiviral drug to give these individuals some protection during the influenza season.
Doctors may also prescribe antiviral medications for people at high risk if:
They may also be prescribed for people who have not been immunized and are in contact with those who are at high risk.
When are antiviral medications used to TREAT influenza?
A doctor may prescribe antiviral medications when a person at risk comes down with influenza. To be effective, medication must be started within 48 hours after the first symptom appears. They are usually given for five days.
Amantadine only works against influenza Type A virus. Unfortunately, some viruses have become resistant to it. Amantadine can be given to children over the age of one year.
However, it cannot be given with certain medications or to people with certain health problems. Possible side effects include nausea, blurred vision, dizziness, difficulty sleeping, decreased appetite, anxiety, confusion, dry mouth, headache and constipation. These may go away during treatment. In older people, amantadine can cause more serious side effects, especially on the nervous system.
Oseltamivir, a newer antiviral medication, is effective against both influenza Type A and influenza Type B. It can be used for children over the age of one year. Oseltamivir can cause nausea, vomiting and dizziness, but these side effects may be lessened if this medication is taken with food.
For more information contact:
Health Link Alberta
Edmonton, call 408-LINK (5465)
Calgary, call 943-LINK (5465)
Outside Edmonton and Calgary local calling
areas, call toll-free 1-866-408-LINK (5465)
visit: http://www.healthlinkalberta.ca/
Public Health Centres
(Monday - Friday, daytime hours), or
physicians or pharmacists
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