3 Things to Avoid After Your Flu Shot to Help Boost Your Immune Response

A yearly flu shot is the best way to protect yourself against the flu. Influenza vaccines lower your risk of getting sick with the flu. And if you do get a breakthrough infection, a flu shot still helps protect you from serious flu illness. 

You may be wondering how to get the most protection from your flu shot. There are things you should avoid after your flu shot to help your immune system respond to the flu vaccine. Here are three things to avoid after getting your flu shot. 

1. Tylenol and Advil

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 arm redness or soreness. 

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

Some 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 their vaccines had a weaker immune response. 

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

But for most people, it’s safe to take these medications if you experience discomfort or fever after your flu shot. Your healthcare team can help you decide if it’s safe to take acetaminophen or ibuprofen after your flu shot. 

2. Alcohol

You’ll want to stay hydrated after your flu shot. Drinking enough fluids can help ease flu shot side effects like muscle aches, headaches, and fatigue. But you want to choose the right fluids to stay hydrated, like water or electrolyte drinks.

Avoid alcohol for 1 to 2 days after your flu shot. Alcohol makes you pee more often, which can put you at risk for dehydration and worsen flu shot side effects like muscle aches and headaches. Alcohol also causes inflammation throughout your body. This can make it harder for your body to recover from flu shot side effects. 

EXPERT PICKS: WHAT TO READ NEXT

• The best time to get a flu shot is the end of October. But here’s why it’s never too late to get your flu shot. 

• Experts recommend getting a flu shot every year. Flu strains are always changing, so getting the updated yearly flu shot is your best chance of avoiding infection.

• When is flu season? In the U.S., flu season generally goes from October through May. Learn how to time your flu vaccine for maximum protection.

Alcohol can also weaken your immune system, making it harder for your body to build antibodies after your flu shot. Avoiding alcohol after your flu shot gives you the best chance at building strong protection against the flu. 

3. Upper arm exercises

It’s safe to exercise after your flu shot. You don’t have to take time off from your regular routine. In fact, some evidence suggests that moderate activity can help boost your immune response to the flu vaccine. 

But it’s important to listen to your body and avoid pushing through pain. Adjust your routine if you experience arm soreness or muscle aches, especially in your arms. Experts recommend sticking to light aerobic exercise immediately after your flu shot. If you’re still free of side effects after 1 to 2 days, you can go back to more intense exercise, including those that target your arm muscles.

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 they’re a sign that your immune system is responding to the vaccine. 

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:

• Hives

• Swelling of the face or tongue

• Itchy throat

• Throat tightness

• Difficulty breathing

• Cough

• Vomiting or diarrhea

• Stomach pain

How soon after a flu shot are you protected?

It takes about 2 weeks for your immune system to fully develop antibiotics against the flu, helping protect you throughout flu season. That’s why it’s important to get your flu vaccine before flu activity peaks in your area. 

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 any time when influenza is spreading — which is usually through May. 

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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:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

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