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Does The Flu Shot Cause Fatigue?

September 6, 2024

With flu season rapidly approaching, many people are getting ready for their annual flu shot to stay protected. While the vaccine is effective in preventing the flu, some people may experience mild side effects afterwards. One common question is– does the flu shot cause fatigue? In this blog, we’ll explore influenza vaccination, discussing the potential side effects so you can better understand what to expect after getting vaccinated.

For a same-day flu shot, visit the walk-in clinic at AFC Urgent Care Ken Caryl. We are dedicated to providing effective flu vaccination for all families in the Littleton, CO area. Just walk-in or plan your visit in advance by scheduling an appointment below!

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How a Flu Shot Works and Common Side Effects

The flu shot contains inactivated (dead) or weakened flu viruses, which are incapable of causing illness. Instead, these viruses stimulate your immune system to produce antibodies that can fight off the flu if you come into contact with it later in the season. The body’s immune response to the vaccine is what helps you stay protected but can also be the reason for minor side effects. That being said, vaccination is the most effective way to prevent getting infected with influenza. Most people who receive the flu shot experience little to no side effects. However, like any vaccine, the shot can cause mild reactions in some individuals.


Common flu shot side effects include:

  • Soreness or redness at the injection site
  • Low-grade fever
  • Muscle aches
  • Headache
  • Mild fatigue

These side effects typically last a day or two and are signs that your body is building immunity to the flu.

Why Do I Feel Fatigued After The Flu Shot?

Fatigue is one of the most commonly reported side effects of the flu shot. While the flu shot does not cause the flu, your immune system goes to work after vaccination, producing antibodies to protect against the virus. This immune response can sometimes leave you feeling a bit run down, similar to how your body might react when fighting off an infection. It’s important to note that post-vaccine fatigue is usually mild and temporary. Most people find that any tiredness they experience goes away within 24 to 48 hours. This fatigue is not harmful and is simply a sign that your immune system is responding as it should.

In order to minimize fatigue after your flu shot, be sure to drink plenty of water before and after vaccination to help your body recover. Get plenty of rest and listen to your body afterward. Support your immune system by eating nutritious foods.

When To Be Concerned With Flu Shot Side Effects

While mild fatigue after the flu shot is common, severe or prolonged fatigue is not. If you experience extreme tiredness, muscle weakness, or other concerning symptoms after getting the flu vaccine, it’s a good idea to consult with a healthcare provider. In very rare cases, people may have allergic reactions to the flu shot, so it’s important to seek medical attention if you notice symptoms like difficulty breathing, swelling, or a high fever. Getting a flu shot is an important step in protecting yourself and others during flu season– so don’t let the fear of mild side effects hold you back! If you’ve experienced an adverse reaction to the vaccination in the past, consult your healthcare provider for additional guidance on flu prevention.

Get a Walk-In Flu Shot at AFC Urgent Care Ken Caryl in Littleton, CO

While the flu shot can cause mild fatigue, this side effect is short-lived and generally not a cause for concern. Fatigue is a sign that your immune system is working to protect you from the flu, and the benefits of getting vaccinated far outweigh the temporary discomfort. Are you prepared for the upcoming flu season? Come visit the walk-in clinic at AFC Urgent Care Ken Caryl for same-day influenza vaccination. When you need preventive care, our team is here. We’re open every day of the week, making flu vaccination and treatment accessible when you need it. Our facility is conveniently located at 9985 W Remington Pl. in Littleton, CO– just walk-in today! We accept most health insurance plans and offer cost-effective options for self-paying patients. If you have any additional questions about the flu shots we provide, simply call us directly at (720) 818-8010.

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