3 Things to Avoid After Your Flu Shot, and What to Do Instead

A yearly flu shot is the best way to lower your risk of getting the flu and developing serious complications from it. It takes about 2 weeks for your immune system to build a full response after vaccination. So, you may be wondering how to get the most protection from your flu shot. 

Most people don’t need to change their routine after getting a flu shot. But a few precautions can help you manage side effects and avoid discomfort. Here’s what you may want to avoid or limit after getting your flu shot — and what you can do to feel better.

1. Drinking alcohol

No amount of alcohol is completely safe to drink. Heavy drinking can weaken your immune system and cause inflammation in your body. Alcohol can also lead to headaches, nausea, fatigue, and dehydration. These effects can overlap with or worsen side effects from the flu shot.

Alcohol also makes you pee more often, which can put you at risk for dehydration and worsen side effects like muscle aches and headaches. 

That said, there’s no official recommendation that you need to avoid all alcohol after getting a flu shot. And research on the topic is limited.

2. Doing intense physical activity before you’re up to it

Most people can safely exercise after getting a flu shot. If you feel up to it, you can continue with your regular physical activity. In fact, some evidence suggests that moderate activity can help boost your immune response to the flu vaccine.

The key is to listen to your body and avoid pushing through pain. Gently moving your arms may help with mild soreness. But consider scaling back your workout if you feel tired, dizzy, or achy. Slowly get back to your exercise routine as you start to feel better. 

3. Taking pain relievers before you need them

Acetaminophen (Tylenol) and ibuprofen (Advil) are over-the-counter (OTC) pain and fever relievers. They can help if you experience side effects from the flu shot, like a headache or arm soreness.

But experts don’t recommend taking these medications before a flu shot unless you need them.

Some animal and lab studies suggest that nonsteroidal anti-inflammatory drugs (NSAIDs), like ibuprofen, could interfere with creating flu antibodies, especially in older adults or people with weakened immune systems. Another study found that children who took acetaminophen before developing any symptoms had a weaker immune response.

It’s not clear whether these lower immune responses actually interfered with how well the vaccine protected people. To be safe, experts recommend against taking acetaminophen or ibuprofen simply to avoid side effects.

For most people, it’s safe to take these medications if you experience discomfort or fever after your flu shot. Ask a healthcare professional if you aren’t sure what’s safest for you.

What to expect after your flu shot

Flu shots can cause mild side effects, like arm soreness and redness. These side effects are usually mild and go away on their own within 48 hours. The most common flu shot side effects include:

• Soreness in the arm where you got the shot

• Fatigue

• Headache

• Muscle aches

• Nausea

• Fever

Flu shot side effects can be uncomfortable. But these mild side effects are a normal sign that your immune system is responding to the vaccine. That said, many people have no side effects at all. Your vaccine protection comes from the antibodies your body builds, whether or not you feel any symptoms. 

When to see a healthcare professional

Serious flu shot side effects are uncommon. But some people have experienced allergic reactions. Allergic reactions need immediate medical attention. 

Call 911 if you experience any of these symptoms after a flu shot:

• Difficulty breathing, wheezing, or throat tightness

• Swelling around your face, eyes, lips, or tongue

• Hives

• Dizziness, weakness, or a fast heartbeat 

What you should do after your flu shot

You can likely go about your day as usual after your flu shot. But if you develop mild side effects, these tips can help:

• Put a cool washcloth on the area where you got the shot. This can help reduce any swelling or stiffness. 

• Gently move your arm to reduce stiffness. But avoid strenuous activity if you aren’t feeling up to it.

• Stay hydrated by drinking plenty of water. 

• Rest and get plenty of sleep. 

How soon after a flu shot are you protected?

It takes about 2 weeks for your immune system to fully develop antibodies against the flu. You can still catch the flu during this time, so it’s important to continue taking precautions around people who are sick. 

In the U.S., the best time to get a flu shot is by the end of October. But it’s almost never too late! You can still benefit from the shot at any point when influenza is spreading, which is usually through May. But it’s still possible to get the flu in the summer, too.

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Written by:

Susan Feinstein, MPH

Susan Feinstein has been writing about health and medicine for more than 20 years, unraveling complex topics into everyday language for consumers. Her work has appeared in Consumer Reports, The New York Times, and The Washington Post.

Edited by:

Alex Eastman, PhD, RN

Alex Eastman, PhD, RN, is a California-based registered nurse and staff medical editor at GoodRx, where he focuses on clinical updates and Latino health.

Reviewed by:

Farzon A. Nahvi, MD

Farzon Nahvi, MD, is an emergency medicine physician and author of “Code Gray: Death, Life, and Uncertainty in the ER.” He works at Concord Hospital in Concord, New Hampshire, and teaches at the Geisel School of Medicine at Dartmouth.

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