5 Medications That Interact With the Flu Shot

Some drugs can make the influenza vaccine less effective

Terry Ann Donner,

Updated July 16, 2026

AARP

Reviewed by

Zachary Cox, PharmD

Comments

En español

Updated July 16, 2026

syringe surrounded by various pills and capsules

Photo Collage: AARP; (Source: Getty Images (2))

Key takeaways

Common medications can blunt your immune response to the flu vaccine and reduce its effectiveness.
Timing matters. A two-week buffer between certain treatments and the flu shot can give your immune system time to respond fully.
Older adults are at particular risk. The overwhelming majority of seasonal flu deaths occur in adults 65 and older.
Work with your doctor to make a plan before flu season begins. It’s important to balance medication schedules with vaccine timing.

Imagine showing up for a pain injection and your pain management physician cancels your appointment because you just received the flu vaccine.

John Meyerhoffer, an 87-year-old retired police officer, used to receive steroid injections every three to four months to manage debilitating knee pain.

On one occasion, he recalls, “I went to my primary care doctor a week before my pain injection. We discussed my upcoming shot, and I got my flu vaccine.”

When Meyerhoffer hobbled into pain management for his steroid injection the following week, he was sent home to wait for two weeks because he had received the flu shot.

Getting a flu vaccine is an annual rite of passage for roughly 67 percent of Americans 65 and older, according to the U.S. Centers for Disease Control and Prevention (CDC). What they may not realize is that several medications can decrease the effectiveness of the flu vaccine.

Work with your doctor before getting the flu vaccine

It is important to share what medications or treatments you are taking with your physician and pharmacist. Given the risk of death or serious complications with the flu, your physician or pharmacist can help you weigh the risk of delaying treatment with medication that could hamper your immune response, versus getting the vaccine while taking such medication.

According to the CDC, 70 to 85 percent of seasonal flu-related deaths occur in older adults. When considering whether to delay a vaccine because of a potential drug interaction, you must weigh the risks and benefits, says Jodie Pepin, director of clinical pharmacy services at Harbor Health in Austin, Texas.

Here are five types of medications that can diminish the protection offered by the flu vaccine.

1. Steroid injections

Steroid injections, also called corticosteroid or cortisone shots, reduce inflammation and pain by delivering medication into a joint or the epidural space around the nerves of the spine. These pain injections typically include a local anesthetic in addition to a steroid that can minimize inflammation and pain for several months in some cases.

A Mayo Clinic study analyzing more than 15,000 patients who received steroid shots for pain in hips, knees, shoulders or other joints found that those who got the injections a few weeks before the flu vaccine experienced a reduction in vaccine effectiveness.

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“When getting an injected steroid in a joint or epidural space, you get some systemic absorption of the medication, which causes a transient dampening of your immune system,” says Dr. William Raoofi of the Center for Interventional Pain Medicine at Baltimore’s Mercy Medical Center. “Then when you are vaccinated and exposed to the weakened flu virus, your immune system is not as good at responding to it.”

When suppressed, your immune system does not effectively recognize the inactive flu virus introduced by the vaccine. Your immune system could then fail to launch a strong attack on the live virus if you are exposed later.

Raoofi says that as you age, your body produces fewer and weaker immune cells that cannot remember the virus you were vaccinated against. Steroids can further weaken your ability to launch a strong immune response to protect yourself if you are exposed to the flu later.

When an older adult comes into his office for a steroid injection and has received or plans to receive the flu vaccine within the next two weeks, Raoofi says, he reschedules the appointment for two weeks after the vaccination.

“It is a risk-benefit decision,” he says. Because of the high risk of death or complications for an older person with the flu, Raoofi says, it is important to leave a two-week window for the immune system to ramp up its response to the flu virus before receiving the steroid injection.

2. Oral prednisone

Prednisone is a steroid that is taken orally to decrease inflammation, suppress an overactive immune system or replace cortisol. It treats conditions like asthma, arthritis and inflammatory bowel disease. Combined with medications like cyclosporine, prednisone also suppresses the immune system after organ transplantation to prevent rejection.

At doses of 20 milligrams per day for two weeks or more, prednisone may decrease your body’s response to vaccines, including the flu vaccine, according to the CDC. “High-dose systemic corticosteroids may suppress immune function and reduce immune response to the flu vaccine," Pepin says.

3. Nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen and high-dose aspirin

Over-the-counter pain relievers and fever reducers, taken before a flu vaccination, may also decrease your response to the vaccine. These medications include acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDS) like ibuprofen (Motrin, Advil) and naproxen (Aleve).

Alcohol and the Flu Shot

Binge drinking (five drinks over a two-hour period for men and four drinks over two hours for women) may weaken the immune system. Even a single binge-drinking episode may impair the body’s ability to fight infection for up to 24 hours, according to the National Institute on Alcohol Abuse and Alcoholism.

“Heavy alcohol consumption may temporarily impair immune function, and limiting excessive alcohol intake around the time of vaccination is reasonable,” says Pepin.

While taking a daily low-dose aspirin (81 mg) before your flu vaccine may be OK, aspirin taken at a higher dose for pain relief (650 mg) could decrease your flu shot response. Consult your doctor on aspirin use before your vaccine.

“When you get the flu vaccine, a lot of people will get a temperature of 99 degrees, malaise and pain at the injection site for up to 24 hours,” says Pepin. “This means your immune system is responding to the flu virus.”

If you are uncomfortable after the flu vaccine, Pepin recommends taking acetaminophen or NSAIDs.

“Current evidence suggests avoiding routine premedication before vaccination, but using these medications after vaccination for symptom relief is generally acceptable,” she adds. “Any reduction in immune response appears small and of uncertain clinical significance.”

4. Chemotherapy and radiation therapy

According to the American Cancer Society, cancer and many of the treatments that treat it can weaken the immune system, making it harder for the body to mount a strong response to vaccines.

If you have cancer, the ACS recommends consulting with your physician about the best time to be vaccinated. Many chemotherapy drugs suppress immune function by affecting rapidly dividing cells, including bone marrow cells that produce immune cells, notes Pepin.

As a result, your body may not produce as strong an immune response to the vaccine, which can reduce its effectiveness and make you more susceptible to the flu.

5. Biologics

Biologics include medications that bind to certain proteins on immune cells to fight cancer cells or the inflammation that results when your own body attacks itself.

Medications like atezolizumab (Tecentriq), avelumab (Bavencio), durvalumab (Imfinzi), ipilimumab (Yervoy), nivolumab (Opdivo) and pembrolizumab (Keytruda) fight cancer. They help the immune system find and destroy cancer cells and may also damage healthy cells.

Other biologics, like etanercept (Enbrel), adalimumab (Humira) and infliximab (Remicade), target a protein that promotes inflammation. By blocking this protein, these medications help reduce inflammation in autoimmune diseases like rheumatoid arthritis, psoriatic arthritis and psoriasis.

Pepin recommends consulting your physician to determine at what point in your therapy you should get the flu vaccine, keeping in mind that settling for limited protection may be better than delaying your vaccine.

Questions to Ask About Drug Interactions Before Your Next Flu Shot

Before flu season begins, get answers — from your health care provider or pharmacist — to the following:

Do any of my current medications require me to adjust the timing of my flu shot?
I receive steroid injections for pain. How should they be scheduled around my flu shot?
Which, if any, of my medications should I temporarily pause or adjust before or after my flu vaccine?
If I’ve had a recent change in my health — say, a new diagnosis, a new medication or a recent illness — does that affect when or whether I should get vaccinated this year?
What is the best time this fall for me to get vaccinated, given my treatment schedule?

Practical Tips for Reducing Risks and Managing Side Effects

Getting the flu shot is essential, but what you do in the days before and after matters too. Here’s how to make the most of your shot and manage how you feel afterward.

What to expect after the shot

Don’t be alarmed if you have mild side effects in the 24 hours or so after you’ve been vaccinated. A low-grade fever of around 99 degrees, fatigue and soreness or redness at the injection site are all signs that your immune system is responding to the vaccine.

Stay hydrated

Drinking plenty of water before and after your vaccine may help prevent side effects after your shots. Dehydration can amplify post-shot symptoms like fatigue and headache, making you feel worse than necessary.

Be cautious with pain relievers

Resist the urge to take acetaminophen, ibuprofen or high-dose aspirin preemptively to ward off discomfort, says Pepin. Taking these medications can blunt your immune response before it has a chance to ramp up. If you’re uncomfortable after vaccination, taking one of these pain relievers is generally OK, says Pepin.

Before and After Your Flu Shot: What to Avoid

Alcohol: Drinking to excess is never a good idea, of course, but it’s especially important to avoid around the time of your vaccination.
NSAIDs: Avoid before the shot; they can blunt your immune response.
Steroid injections: Discuss with your doctor if you need to allow time between injections on either side of your flu shot
Heavy exertion: Avoid intense exercise only if you experience symptoms such as fever, significant fatigue or injection-site swelling. Mild soreness alone is not a reason to rest.

Who Needs a Flu Shot?

The short answer: Pretty much everyone.

The CDC recommends that everyone 6 months and older get a flu vaccine every year (ideally in September or October), with rare exceptions. Vaccination is particularly important for people who are at higher risk of serious complications from the flu.

But keep in mind that “recommended for all” isn’t the same as “one size fits all.” Your age, overall health, where you live and work and immune status all determine how urgently you need the shot — and which formulation is right for you. Those in particular need of a flu shot include:

Older adults

According to the CDC, 50 to 70 percent of flu-related hospitalizations occur in older adults, which helps explain why getting a flu shot every year is so strongly recommended for people 65 or older.

The CDC and the federal Advisory Committee on Immunization Practices (ACIP) recommend that adults 65 and older receive one of three higher-dose or adjuvanted influenza vaccines when available: the high-dose inactivated influenza vaccine, the recombinant influenza vaccine or the adjuvanted inactivated influenza vaccine.

People with chronic conditions

Chronic conditions — including asthma, chronic obstructive pulmonary disease (COPD), heart disease, diabetes, kidney disease, liver disease, neurologic disorders, compromised immune systems and obesity — all raise the risk of getting the flu. According to the CDC, 89 percent of hospitalized flu patients in a recent season had at least one underlying medical condition.

People with a compromised immune system

If you have a weakened immune system — whether it’s because of chemotherapy, organ transplantation, biologics or HIV — you face a double challenge: Not only are you more vulnerable to severe illness if you get the flu, but your immune response to the vaccine may be blunted.

Inactivated and recombinant influenza vaccines are generally considered safe for immunocompromised people, but the live attenuated nasal spray vaccine should not be used, according to the CDC. Talk to your doctor before flu season begins to schedule your flu shot.

People who live or work in high-contact settings, including caregivers

Health care professionals, teachers, and first responders, among others in high-contact environments, have both personal and public health reasons to get vaccinated.

The ACIP recommends that health care professionals receive an annual flu shot. So, too, should caregivers and other household contacts of people who are immunocompromised or otherwise vulnerable. Vaccinating yourself protects those around you who may not be able to protect themselves.

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