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How the flu shot strengthens your immune system

Getting a flu shot each year reduces your risk of contracting the flu as well as spreading it to those around you. In Canada each year, nearly 20,000 people are hospitalized because of the flu, and 2,000 to 8,000 people die from complications. These numbers underscore the flu shot’s importance. Here’s how the flu shot helps protect you from getting the flu.

how to flu vaccine works
How the flu shot works

Influenza (flu) vaccinations come in two forms: the flu injection vaccine and the nasal spray flu vaccine. The flu shot contains inactive, or dead, viruses, while the nasal spray flu vaccine contains live, weakened viruses. Each one contains three different flu viruses that medical experts around the world have determined to be the highest threat for that year. Injected or sprayed into your body, the flu vaccine stimulates your immune system to produce antibodies to protect you from the viruses. Later, if you are exposed to these flu viruses, your body remembers them and is able to fight them off and prevent you from becoming sick.

Why you need a flu shot every year

Over time, the effects of the flu shot can wear off, and you’ll need to be protected again before the new flu season begins. Also, each year, the flu shot is composed of three different flu viruses that are considered to be the highest threat. This changes from year to year, and you need protection from the currently circulating strains. The Public Health Agency of Canada advises people to get their flu shots early, in October or November, because the shot can take up to two weeks to become effective in your system. If you are unable to get it early, getting it at some point during flu season is better than not getting it at all. The flu season runs from October to May, so make sure you are protected as soon as possible.

Targeted protection

The flu shot protects you from only the three strains of flu viruses that it contains for that year. Viruses are constantly evolving and developing, so many strains exist; however, the flu shot will protect you from the most common strains that scientists and the medical community believe will pose the most danger for that flu season. Even though the flu shot does not protect you from all strains of flu, it will help protect you, and those around you, from spreading the most common three strains.

Who should get a flu shot

The National Advisory Committee on Immunization advises all Canadians over 6 months old to get a flu shot, especially those who are in the high-risk group. These include:

  • Pregnant women
  • Children under 5
  • People age 50 and older
  • People with chronic illnesses or conditions
  • People who live with or care for high-risk individuals

The nasal spray flu vaccine can be given to healthy people between the ages of 2 and 49. Pregnant women should not get the nasal-spray vaccine.

More articles of interest

Who needs a flu shot?
Flu shot risks
Can I get a flu shot while pregnant?

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