3 Things to Avoid After Your Flu Shot to Help Boost Your Immune Response
Key takeaways:
The yearly flu vaccine is the best way to protect yourself from the flu, which is caused by an influenza virus.
You may need to adjust your routine on the day of your flu shot. Experts recommend avoiding alcohol and vigorous exercise immediately after your flu shot.
Flu shot side effects may last a few days. Over-the-counter (OT) pain relievers like acetaminophen and ibuprofen can help ease discomfort.
Table of contents
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.
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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.
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.
Frequently asked questions
Flu vaccine effectiveness varies from year to year. It depends on how well the vaccine matches the type of flu going around that season.
Yes, you can get the flu shot if you have a cold. Your immune system can fight off a mild illness while also responding to a vaccine. But people with weakened immune systems or more serious illnesses may need to wait. Your healthcare team can help you decide if it’s safe to get a flu shot while you’re sick.
No, you can’t get the flu from a flu shot. Flu shots, including nasal sprays, contain either dead or weakened viruses. A dead or weakened virus can’t cause an infection.
The bottom line
Getting the flu shot doesn’t usually get in the way of your usual activities. But avoiding alcohol and intense arm exercises right after your flu shot may help reduce flu shot side effects. You can take OTC pain and fever relievers if you experience flu shot side effects. But experts recommend only taking these medications if needed, as they may affect your immune response.
Why trust our experts?
References
AAP Grand Rounds. (2010). Prophylactic acetaminophen may blunt immune response to vaccines.
Bernard, M. P., et al. (2010). Inhibition of cyclooxygenase-2 impairs the expression of essential plasma cell transcription factors and human B-lymphocyte differentiation. Immunology.
Centers for Disease Control and Prevention. (2024). Flu season has started but there’s still time to benefit from getting a flu vaccine.
Centers for Disease Control and Prevention. (2024). Influenza (flu) vaccine safety.
Centers for Disease Control and Prevention. (2024). Key facts about the seasonal flu vaccine.
Hallam, J., et al. (2022). Exercise after influenza or COVID-19 vaccination increases serum antibody without an increase in side effects. Brain, Behavior, and Immunity.
Saleh, E., et al. (2016). Effect of antipyretic analgesics on immune responses to vaccination. Human Vaccines and Immunotherapeutics.
Sarkar, D., et al. (2015). Alcohol and the immune system. Alcohol Research.
UnityPoint Health. (n.d.). 6 ways to prevent arm soreness after a vaccine.
