The Issue
Influenza (or flu) is a common respiratory illness that affects millions of Canadians every year. Getting an annual influenza vaccination (or flu shot) can help prevent an infection or reduce the severity of the illness.
Background
Influenza is a respiratory infection caused by the influenza virus. Various strains of the virus circulate throughout the world -- causing local outbreaks -- year-round. In Canada, flu season usually runs from November to April, and an estimated 10-25% of Canadians could have the flu each year. Although most of these people recover completely, an estimated 4 000 to 8 000 Canadians -- mostly seniors -- die every year from pneumonia related to flu. Many others may die from other serious complications of flu.
The influenza virus spreads through droplets from someone with the flu, who coughs or sneezes into the air. You can become infected by breathing in these droplets through your nose or mouth, or through the droplets landing directly on your eyes. The flu virus is also found on the hands of people with the flu and on surfaces they have touched. You can become infected if you shake hands with infected persons or touch contaminated surfaces, which can transfer the virus to your own eyes, nose or mouth.
Flu vaccines have been around since the 1940s. The vaccine is made from fragments of inactivated influenza viruses, grown in fertilized hens' eggs and then purified. The flu viruses are capable of changing from year to year, so the composition of the vaccine has to be updated annually. This is why it is necessary to be immunized every fall. About 10 million doses of influenza vaccine are distributed annually during the flu season, in Canada.
After you get a flu shot, your immune system produces antibodies against the strains of virus in the vaccine. When you are exposed to the influenza virus, these antibodies will help to prevent infection or to reduce the severity of the illness.
The Health Effects of Influenza
There is no such thing as the "stomach flu." Many people use the terms "flu" or "stomach flu" to describe other illnesses that may actually be a common cold or a mild case of food poisoning.
These are the symptoms of influenza
Almost always
- Cough and fever
Common
- Fatigue
- Muscle aches
- Sore Throat
- Headache
- Decreased appetite
- Runny nose
Sometimes
- Nausea
- Vomiting
- Diarrhea
Most people recover within a week or ten days. However, some are at greater risk for more severe and longer-lasting complications, such as pneumonia. The groups at higher risk include very young children, people over 65, pregnant women, people with underlying medical conditions such as chronic respiratory disease, heart or kidney disease, diabetes or a weakened immune system due to cancer, HIV infection, or some other cause.
Another possible health effect related to the flu is Reye's syndrome, which can develop in children and teenagers who are given salicylates (aspirin) when they have the flu or chickenpox. Reye's syndrome affects the central nervous system and the liver, and can be fatal. Do not give aspirin to children or teenagers with the flu, unless you are specifically directed to do so by a doctor.
Minimizing Your Risk
Immunization is one of the most effective ways to protect against influenza. When you are immunized, you have received a vaccine (sometimes called a shot) containing a dead or weakened virus to help your body learn how to fight off the virus if you are exposed to it.
Vaccines are virus-specific, so to protect against both seasonal flu and the pandemic H1N1 flu virus, you will need two separate flu shots.
The most effective way to protect yourself from flu is to be vaccinated each year in the fall. Every year, the vaccine is formulated to protect against the most commonly circulating flu viruses. Seasonal flu shots are especially important for:
- children aged 6 to 23 months;
- adults and children with chronic heart and lung disease;
- anyone living in a nursing home or chronic care facility;
- people aged 65 years and older;
- people with chronic conditions such as diabetes, anemia, cancer, immune suppression, HIV, or kidney disease;
- children and adolescents on long term acetylsalicylic acid (ASA) therapy;
- healthy pregnant women;
- health care workers, other caregivers, and household contacts capable of transmitting influenza to the above at-risk groups;
- people at high risk of influenza complications who are traveling to areas where the flu virus is likely to be circulating.
Certain groups should not be vaccinated. These include children under six months of age and people who have had a severe allergic reaction to eggs or a previous dose of the vaccine. The timing of the seasonal flu vaccine campaigns for the 2010/11 flu season will vary across the country. Please check with the health authority in your region for further information.
Treatment
If you get the flu, you should increase the amount of fluids you drink (water, juice, soups) and get plenty of rest for seven to ten days. There are also medications to treat influenza. If you take them within 48 hours of the start of your symptoms, they may reduce the length of your illness by an average of one or two days.
Canada has a national stockpile of these drugs, called antivirals, for the treatment of moderate to severe pandemic influenza. This stockpile contains 55 million doses of two different kinds of drugs, Tamilfu and Relenza, which is enough to treat everyone who needs it during a pandemic. Antivirals are not recommended for the treatment of mild illness.
For more information, contact your local public health department or your health care provider.
Also, visit the Fight Flu Web portal. The portal provides you with access to information on flu, as well as links to resources from the provinces and territories. You can also call the Public Health Agency of Canada's Information Line at 1-800-454-8302 (toll-free in Canada) for information about seasonal flu, the H1N1 influenza pandemic, and Avian flu.
This article comes from the Health Canada website.
