What Are the Side Effects of the Flu Vaccine?

Talor Bianchini
Talor Bianchini23 Aug 2022

Getting a flu vaccine each year is the best way to keep yourself and others safe from the seasonal flu. Flu vaccines have an excellent safety record, and hundreds of millions of Americans have received them since their creation. Some people may experience mild side effects from the flu vaccine, such as muscle aches, a low-grade fever, or a runny nose. 

If you are trying to get your flu shot, Mira can help you locate free or low-cost flu vaccines near you. In addition, Mira members get access to affordable urgent and virtual care, lab tests, discounted prescriptions, and more. Stay safe and healthy with Mira – sign up today. 

Side Effects of the Flu Vaccine

Influenza, typically referred to as the seasonal flu, is a highly contagious respiratory illness. It generally is most prevalent from October through May and affects 3 to 11 percent of the population each year. The best way to protect yourself and those around you from the flu is by getting a flu vaccine each year. The flu vaccine can prevent you from contracting, spreading, and becoming very ill from the flu. The CDC recommends that everyone ages six months or older get a flu shot. 

As with any effective vaccine, you may get potential side effects from the flu shot. Side effects occur because the vaccine initiates an immune response in your body to help protect you from future infection. Side effects may differ depending on your age or other medical conditions. 

In addition, the flu vaccine can either be administered through an injection or nasal spray. The side effects may differ depending on what type of immunization you receive. Below we outline the side effects of the injection and nasal spray flu vaccine. 

Flu Vaccine Injection Side Effects

The flu vaccine is typically given by injection in the muscle of your arm. There are multiple versions of the injection available, depending on your age and whether or not you are allergic to eggs. The shot contains killed flu viruses or particles designed to look like the flu virus. These particles stimulate an immune response in your body, and as a result may result in some mild side effects, which can include: 

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

Not everyone who gets a flu shot will experience symptoms from the flu shot. These symptoms may last anywhere from 1 to 2 days. If any of your symptoms persist or get worse after two days, you should contact a healthcare professional. 

Flu Vaccine Nasal Spray Side Effects

Unlike the flu shot, the nasal spray vaccine contains the live flu virus. The viruses in the nasal spray are weakened and changed, therefore preventing them from being infectious. As a result, people may experience different side effects from the nasal spray vaccine, which may be more ‘flu-like.’ These side effects can include:

  • Runny nose
  • Fever
  • Headaches
  • Muscle aches
  • Vomiting
  • Wheezing
  • Sore throat

It is important to note that the nasal spray vaccine is not advised for everyone. People who should not get the nasal spray flu vaccine include: 

  • Pregnant women
  • Adults over the age of 50
  • Children under the age of 2
  • People with weakened immune systems
  • Kids ages 2 to 4 that have had asthma or wheezing in the past 12 months
  • Children between the ages of 2 and 17 that are currently taking aspirin or medication containing salicylate
  • People with certain chronic medical conditions

Severe Side Effects 

In very rare cases, people can experience an allergic reaction to the flu vaccine. Allergic reactions can include dizziness, ringing in the ears, changes in vision, and fainting. These side effects will typically occur immediately after receiving the injection. The side effects go away fairly quickly, and lying or sitting down may help alleviate symptoms. 

Both injection and nasal spray flu vaccines are manufactured with egg-based technology. Therefore, they contain small amounts of egg proteins, potentially harmful to those with severe egg allergies. Although rare, some may experience an allergic reaction to the vaccine immediately following vaccination. The CDC recommends that those with a known allergy receive an age-appropriate recommended flu vaccine. If you have a history of a severe allergic reaction, the vaccine should be given in an inpatient or outpatient medical facility. 

Finally, about one out of every million people who receive the flu vaccine develop GBS. Guillain-Barré Syndrome (GBS) is a rare disorder that damages the nerve cells. Many people recover from the disease, but some may experience long-term nerve damage. If you experience more than one of the following side effects after your flu shot, contact your doctor immediately:

  • Bruising or hard lump at the injection site
  • Large, flat, blue/purple patches on the skin
  • Vomiting
  • Loss of appetite
  • Irritability
  • Loss of voice
  • Shivering
  • Difficulty swallowing
  • Fast heartbeat
  • And more

Preparing For The 2021-2022 Flu Season

Last year, the flu season was relatively mild, so many people expect to see higher flu cases this year. This is especially true now that previous COVID-19 precautions like hand washing, masking, and social distancing are becoming more relaxed. The CDC reported that all flu vaccines will be quadrivalent, meaning they will protect against four different flu viruses. You can get a COVID-19 vaccine or COVID-19 booster and flu vaccine at the same time. 

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Where to Get a Flu Vaccine

There are many different places where you can get a flu shot. All major pharmacies distribute the flu vaccine during the flu season, including Walmart, CVS, Walgreens, and Rite Aid. Other stores, such as Target and Giant, administer the flu shot as well. You can also receive a flu shot at your doctor’s office, an urgent care center, or your local health department. If you are in college, your school will most likely set up a flu vaccine clinic at the start of the fall months. Most of these places will offer the vaccine for free if you have insurance or a small fee if you pay without insurance.

Other Ways to Protect Against the Flu

In addition to getting the flu vaccine, there are other precautions you can take to protect yourself from the flu each year. These tips will also help to prevent other viruses, like COVID-19. Some steps you can take to avoid the flu include:

  • Avoiding touching your eyes and mouth
  • Washing your hands often and thoroughly for at least 20 seconds
  • Avoiding close contact with those who are sick
  • Clean and disinfect regularly touched surfaces often (countertops, doorknobs, light switches, etc.)
  • Practice healthy habits (drink enough water, exercise regularly, get enough sleep, eat healthy foods)

Flu Vaccine Frequently Asked Questions (FAQs)

Below we address some common questions regarding the flu vaccine and its potential side effects. If you have additional questions about the flu vaccine, you should speak to your health care provider. 

Why should I get the flu vaccine every year?

Influenza viruses can evolve very quickly; therefore, the vaccine that protected against the virus last year may not be effective this season. Each year, scientists develop new flu vaccines to protect against the adapting flu viruses and what they believe will be common strains. In addition, although your body is producing antibodies from the vaccine, the levels in your body decline over time. It is essential to get the flu shot each year to offer the highest protection against the most common strain of the flu.  

Will I get the flu from the flu vaccine?

No, you cannot get the flu from the flu vaccine. The flu shot contains inactivated or dead flu viruses, so they are not infectious. Although you may experience side effects afterward, these are typically mild and common after any vaccination. 

On the other hand, the nasal spray contains the live flu virus, but they are weakened and do not cause infection with the flu. Side effects from this vaccine will be more flu-like but will not be as severe or last as long as the flu. 

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How much does it cost to get a flu vaccine?

The cost of a flu vaccine can vary depending on where you get vaccinated. We found that the average cost without insurance for a flu shot is $70, but prices can range from about $20 to $80. The price may vary depending on the type of flu vaccine you are getting and additional fees. Insurance companies will almost always cover the cost of a flu shot. If you don’t have insurance, there are many ways you can save on vaccines, including the Vaccines for Children Program, prescription savings cards at pharmacies, or state immunization programs. 

How effective is the flu vaccine?

The flu vaccine’s effectiveness varies each year due to the evolving nature of the influenza virus and because scientists predict which viruses will be most prevalent each flu season when manufacturing the vaccine. Studies show that the flu vaccine reduces the risk of flu illness by 40 to 60 percent. Even if you get the flu with the vaccine, your symptoms will be much more mild and manageable. 

Should pregnant women get the flu vaccine?

Yes. The CDC recommends that pregnant women receive the flu vaccine to protect themselves and their babies from getting the flu. However, it is advised that they do not receive the nasal spray vaccine. 

Bottom Line

The most effective way to prevent yourself from getting the flu each year is by getting a flu vaccine. Flu vaccines cannot cause you to get the flu, but you may experience mild symptoms like headaches, muscle aches, or a runny nose caused by your immune response to the vaccine. It is recommended that everyone six months and older receives a flu vaccine each year. 

If you are trying to get a flu shot, Mira can help you find an appointment. In addition, Mira can help you save on urgent care visits, prescription medications, and routine lab tests. Keep yourself healthy this flu season -  sign up for Mira today.

Talor Bianchini

Talor graduated from Penn State University with a B.S. in Biobehavioral Health, and minors in Spanish and Diversity & Inclusion in May of 2022. She has a passion for health equity and diversity in health. In the future, Talor hopes to work in public health policy reform to help eliminate health disparities. She enjoys reading, cooking, and listening to podcasts in her free time.