It’s getting cold out there and lots of folks are considering a flu shot as flu season kicks into high gear.  There are things you can do to avoid getting sick like washing your hands for example, but another thing is considering getting a flu shot. But how exactly does the flu shot work and what is the flu?


The flu is a contagious respiratory illness that can cause symptoms including fever, coughing, chills, body aches, and fatigue. Some people who get the flu recover without complications in about one to two weeks. But the flu can be dangerous for young children and people over the age of 65. Some flu-related complications are also life-threatening.

It’s important to arm yourself with as much knowledge as possible. This way, you know how to better protect yourself.

While many people get the flu at least once in their lifetime, you might not know everything about this illness. Here are some things about the flu to consider…

Flu Season

Between the months of October and May are considered to be “flu season”.

The Flu is Contagious Before You Know You Have It

The flu is highly contagious partly because it’s possible to pass the virus on before you become sick. According to the Centers for Disease Control and Prevention (CDC), you can infect someone with the virus one day before your symptoms start.

You’re most contagious within the first three to four days of becoming ill, although you may remain contagious for up to five to seven days after you become sick. It’s important to avoid close contact with others to prevent passing the illness to another person.

Flu Symptoms Can Happen Fast

The onset of flu symptoms can happen rapidly. You may feel fine one day, and be unable to do anything one or two days later due to your symptoms.

Sometimes, the onset of symptoms occurs as early as one day after exposure. In other cases, some people don’t show symptoms until four days after exposure to the virus.

What is the Flu Shot?

The flu shot is a vaccine — a substance that helps to create an immunity to certain diseases and illnesses in people. Once you are immune to a disease, you can’t catch it. The flu shot is a vaccine that helps to prevent you from getting the influenza virus, which causes the flu. Vaccines are given through a shot, which is a needle that injects the vaccine into your body, usually through your arm.

How does the flu shot work?
The flu shot works by introducing your body to tiny little parts of different flu viruses. This triggers a reaction from your immune system — the processes in your body that fight off infection. Your immune system realizes these virus fragments shouldn’t be in your body, and figures out how to destroy them. In the process, it learns and remembers how to fight off viruses like this in the future.

As a result, if you’re exposed to that kind of virus again, your body already knows how to take care of it, and can destroy the virus before you actually get sick. This is how vaccines work. They give your body a virus or bacteria that is either dead or otherwise deactivated. That way, the virus or bacteria can’t actually get you sick, but your body can still recognize it and learn how to fight it.

Why do some people still get the flu after receiving the shot?

Every year, scientists develop a new flu shot. This is because the flu virus is constantly mutating. That means it changes and develops all the time. As a result, it’s impossible to know which strains are going to spread the most during any given flu season. Scientists make a vaccine using strains that they think are most likely to get people sick, but sometimes a strain they didn’t consider spreads more and people still get sick.

Also, the influenza virus isn’t the only virus that creates similar symptoms. You might get a flu shot and still get a common cold, which can feel a lot like the flu. Because of this, some people think the flu shot didn’t work, even though it did. It’s important to remember that no medicine is 100% effective 100% of the time. That said, it’s reported that you are less likely to get the flu if you get the flu shot.

Are there any side effects?

Just like with any medicine you take, the flu shot does have some potential side effects. Most of them are fairly minor like soreness around where you got the needle and some flu-like symptoms. Feeling a little flush actually means the vaccine is working. Those light symptoms are just your body figuring out how to deal with the virus. More serious side effects can include allergic reactions, but they are really rare. That said, if you experience an allergic reaction, call a doctor immediately.


Where to get a flu shot?
During flu season you can get a free flu shot from:

your family doctor
many pharmacies
Public Health Units
walk-in medical clinics

For more information about the flu shot and deciding whether it is right for you visit the government of Canada’s public health services website HERE.

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