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Does the Flu Shot Cause You to Have the Flu?

I have heard a question countless times in the office that comes up each year when the new flu shot is out. You may have asked this question yourself: Does the flu shot cause you to have the flu? The truth is the flu shot does not give the actual flu, but can protect you from a life threatening virus.

Each year the CDC produces a new version of the flu vaccine that is made with the intention of protecting millions of people from the strands of flu that are likely to emerge during the year’s flu season. Sometimes they get the specific strands right, but there have been times they get it wrong. Either way, we know that by getting the flu shot, people are less likely to get the flu and if they do get the the virus the symptoms are less severe.

You may also be wondering why we have to get a flu shot every year. Well, there are two reasons. Each year when we are given the flu shot, our body then creates antibodies whose sole purpose is to recognize and then fight the flu virus. By having a flu shot each year, your body then can be reminded to gear up for the flu season by making new antibodies. Another reason to get the flu shot yearly is because the flu is a virus that can change over time. It survives by making small mutations within its’ make up. This way our immune system can be tricked and not have the antibodies ready to fight the new version of the flu.

Understanding this, we can now see why health professionals encourage getting the flu shot. But why does it feel like once we get the shot, we may have the flu?

When you get the flu shot, the contents of the vaccine contain inactivated flu strains that cannot be activated to cause the flu. There also other ingredients like eggs and other ingredients that may cause a reaction. Due to the vaccine having stands of the dead flu virus, our body can then make the antibodies needed to fight the flu. Within a 2-week period, the antibodies are generated and may cause you to feel symptoms as if you are “sick”.

Here are some common symptoms that you can get:

  • Soreness, redness, and/or swelling from the shot.

  • Headache.

  • Fever.

  • Nausea.

  • Muscle aches.

Even with all these symptoms let’s be crystal clear. Getting the flu shot DOES NOT mean we are giving you the real, knock you out, live flu virus. However, if you do find that you having a severe reaction to the flu shot, you should contact a health professional for further evaluation.

To learn more information about the flu virus, go to:

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