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Kathleen Berger, MD

Medically reviewed by:
Kathleen Berger, MD

The flu shot is a safe and effective way to prevent illness, but how you care for yourself afterward can influence your body's ability to build immunity to the flu.

June 3, 2025

Getting your annual flu shot is one of the most effective ways to protect yourself and those around you from seasonal influenza. Influenza, or the flu, is more than just an inconvenience—it’s a serious illness that can lead to hospitalization and, in some cases, even death.

While the flu vaccine doesn’t guarantee 100% protection from the flu, it significantly reduces the severity of illness if you do catch it. In fact, a 2021 study found that flu vaccination in adults was associated with a 26% lower risk of ICU admission and a 31% reduction in the risk of death compared to those who didn’t receive the flu vaccine.1 To ensure the vaccine protects you, you should know what to avoid after getting the flu shot. Let’s dive into what you need to steer clear of after receiving the flu shot and why.

After getting your vaccine

The flu shot is a safe and effective way to prevent illness, but how you care for yourself afterward can influence your body’s ability to build immunity to the flu. After receiving your shot, it is normal to feel a bit off. This is a good sign that your body is responding to the vaccine and building defenses against the flu virus.

While most people experience no side effects, some may feel mild soreness, fatigue, or low energy. These side effects are temporary and can be easily managed.

After getting the flu shot, it’s important to listen to your body and permit yourself to rest if you’re feeling achy or fatigued. Stay hydrated and eat a balanced diet, including nutrient-rich foods like leafy greens, fresh fruits, lean proteins, and whole grains, to give your immune system the fuel it needs. Drinking plenty of water not only helps your immune system work at its best but can also help ease minor side effects like fatigue or soreness. Keep a water bottle handy to sip throughout the day.

Remember, the vaccine takes about two weeks to become fully effective.2 During this time, you’re still susceptible to infection, so continue practicing good hygiene habits to reduce your risk of infection, including washing your hands regularly and avoiding close contact with people who are sick.

What you should avoid after getting the flu shot

There are typically no restrictions after receiving your flu shot. However, there are some things you may want to avoid to help your body build up maximum immunity to the flu.

Strenuous exercise

While moderate activity like walking or yoga is fine, you might want to avoid intense workouts or heavy lifting for the first 24–48 hours, particularly if you’re experiencing soreness in your arm. Strenuous activity can temporarily weaken your immune system and may reduce the vaccine’s effectiveness.

Alcohol consumption

While it might be tempting to enjoy a drink after your vaccination, it’s best to avoid alcohol for at least 24 hours after receiving your flu shot. Alcohol can interfere with your immune system’s response to the vaccine, making it harder for your body to build the necessary antibodies.

It can also lead to dehydration, potentially making any side effects feel worse. If you choose to drink, do so in moderation and make sure you’re staying well-hydrated.

Medications

While medications like ibuprofen (Advil) or naproxen (Aleve) can help with soreness or fever, some experts suggest avoiding them unless necessary. Research indicates that anti-inflammatory medications may interfere with the immune response triggered by the vaccine.3,4,5 If you’re experiencing discomfort, such as a sore arm or a mild fever, it’s a good idea to talk with your health care provider before taking any medication.

Side effects

While a flu vaccine cannot give you flu, it can commonly cause mild side effects, including soreness or swelling at the injection site, fatigue, mild fever, headache, or muscle aches.6 After receiving the flu shot, you should monitor yourself for side effects for at least 48 hours, as most mild symptoms typically appear and resolve within this time frame.7

Here’s what to expect and how to manage them:

Common side effects

  • Soreness, redness, or swelling at the injection site
  • Fatigue
  • Low-grade fever
  • Headache
  • Muscle aches

Managing side effects

Apply cold compresses: Use an ice pack on the injection site to reduce swelling in the first 24 hours. After that, switch to warm compresses to relax the muscles and improve blood flow.

Keep your arm moving: Gentle arm movements and light stretches can help reduce soreness and prevent stiffness.

Over-the-counter medications: If you experience low-grade fever, headache, or muscle aches, rest, stay hydrated, and consider taking acetaminophen (Tylenol) to help alleviate symptoms.3

When to seek medical attention

While most side effects from the flu shot are mild and resolve within a day or two, it’s important to be aware of signs that may need medical attention.6

Severe allergic reactions are extremely rare but may occur and require prompt medical attention. Watch for signs such as difficulty breathing, rapid heartbeat, swelling of the face or throat, or hives, as these may indicate a serious reaction.

Persistent or high fever (above 101°F or 38°C) lasting more than 24 hours, severe headaches, or unusual behavior changes should also prompt a call to your health care provider.

Symptoms like tingling, weakness, or difficulty walking could signal a rare condition called Guillain-Barré Syndrome that needs urgent evaluation. The flu vaccine can increase the risk of this condition, which is estimated to only affect 1 to 2 additional people for each million doses of the flu vaccine given per year.8 However, research indicates that you are more likely to develop Guillain-Barré Syndrome after contracting the flu than after receiving the flu vaccine.9

Additionally, watch for symptoms such as chest pain, persistent dizziness, or fainting, as these symptoms might indicate a more serious issue.

If you notice any of these warning signs, contact your health care provider or seek medical care immediately.

The flu shot is a safe and effective way to protect yourself, with minimal side effects. While minor side effects might be inconvenient, the benefits of the flu vaccine far outweigh the risks. The vaccine reduces your chances of severe illness, hospitalization, and complications from the flu.

Protecting yourself from the flu is an important step toward better health, and we’re here to support you every step of the way. If you have any questions or concerns about the flu shot or how to care for yourself afterward, don’t hesitate to schedule an appointment with one of our health care providers by calling 1-888-781-9355. They can provide personalized advice and ensure you’re on the right track to a healthy flu season.

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