Getting a flu shot is one of the most effective ways to protect yourself from seasonal influenza, but like any vaccine, it can come with mild side effects. Many people experience soreness at the injection site, fatigue, or low-grade aches shortly after receiving the vaccine. While these reactions are usually short-lived, understanding what to expect can help you feel more prepared and avoid unnecessary worry.

For same-day flu testing and treatment, visit the walk-in clinic at AFC Urgent Care Cedar Grove. Our medical team is here 7 days a week to provide immediate medical care. No appointments are required, just walk-in today!

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What Are the Common Side Effects of Flu Shot?

The most common flu shot side effects are generally mild and temporary. They include:

• Soreness, redness, or swelling at the injection site
• Low-grade fever or chills
• Fatigue or weakness
• Headache or mild body aches
• Nausea or mild upset stomach

These symptoms are signs that your immune system is responding to the vaccine, building protection against the flu virus.

How Long Might Flu Shot Symptoms Last?

For most people, flu shot side effects last 1–3 days. Soreness at the injection site is usually the longest-lasting symptom, sometimes continuing for a few days after other symptoms fade. Mild fatigue or aches may come and go but typically resolve within a day or two. Severe or prolonged side effects are rare, and if symptoms persist beyond a few days, it’s worth consulting a healthcare provider.

Is It Possible to Have an Allergic Reaction to a Flu Shot?

Although rare, some people may experience allergic reactions to the flu vaccine. Signs of a severe allergic reaction can include:

• Difficulty breathing
• Swelling of the face, lips, or throat
• Severe rash or hives
• Dizziness or fainting

If any of these symptoms occur, seek immediate medical attention, as an urgent care or emergency facility can provide treatment for allergic reactions. Most mild reactions, like itching or a minor rash, resolve on their own within a day or two.

Can a Flu Shot Weaken My Immune System?

No, a flu shot does not weaken your immune system. In fact, it strengthens your body’s ability to fight influenza. Mild side effects, such as fatigue or low-grade fever, are temporary signs that your immune system is activating and building protection. These reactions are normal and indicate that the vaccine is working as intended.

Visit AFC Urgent Care Cedar Grove For Walk-In Flu Symptom Relief

Most flu shot side effects are mild and resolve quickly, but you should visit urgent care if you experience severe or persistent symptoms, especially signs of an allergic reaction. Medical professionals can provide treatments such as antihistamines, epinephrine, or other supportive care to prevent complications. Seeking timely care ensures your safety and peace of mind after vaccination.

Come visit the walk-in clinic at AFC Urgent Care Cedar Grove. Our urgent care center is open 7 days a week and operates on a walk-in basis– no appointments necessary. We accept most health insurance plans and offer low-cost options for self-paying patients. If you have any additional questions about the services we provide, please contact our medical team directly at (973) 239-2300.