Can getting the flu shot make you tired

Below, Dr. Carmen Teague, specialty medical director at Atrium Health's Mecklenburg Medical Group, shares what you need to know about common flu shot side effects that are normal, and which side effects may be a sign of something more serious. 

Read more: 6 Best Vitamins for Flu Season

Common flu shot side effects 

Repeat: The flu vaccine won't give you the flu, but you can experience mild symptoms because of how the vaccine works. 

"The flu vaccine is designed to stimulate your immune system to build antibodies to the virus. That stimulation can cause a low-grade fever, a decrease in appetite, loose stool, mild fatigue or myalgia (muscle ache) and even a scant cough," Teague said.

According to Teague, these symptoms usually resolve after a few days and are no cause for alarm. You may also experience some redness, swelling or soreness where the shot was injected, which is also normal. 

The CDC says you can experience "flulike" symptoms after getting the vaccine, such as:

• Soreness, redness, and/or swelling at the injection site
• Headache
• Fever
• Nausea
• Muscle aches

The symptoms listed above should resolve in a few days. Also, keep in mind not everyone has symptoms, but those are the most common. When it comes to other symptoms, or symptoms that last longer, it's important to keep in mind that you can still catch a cold, or other virus, right after you get the flu shot. 

So if you experience other symptoms that seem like the flu, it could be another illness and it doesn't mean the shot made you sick. The flu shot also takes about two weeks to become effective at protecting you from the flu, so you could technically catch the flu within that two-week window.

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Signs of a more serious (but rare) reaction

"A very small percentage of people can have a true allergic reaction to the vaccine, including chest tightness, difficulty breathing, wheezing, facial or throat swelling and redness of the eyes," Teague said. If you experience these symptoms, you should seek medical attention immediately. Teague says severe allergic reactions usually happen within a few hours of getting the flu shot.

Signs of a severe allergic reaction, according to the CDC, can include:

• Difficulty breathing
• Hoarseness or wheezing
• Swelling around the eyes or lips
• Hives
• Paleness
• Weakness
• A fast heartbeat or dizziness

Another possible reaction is an infection where the shot was administered. "Patients can also develop an infection at the injection site, which is manifested as worsening redness, swelling, warmth and tenderness," Teague said. You should also seek immediate medical attention for this type of reaction. (If you're not sure if it's the common, harmless redness-and-swelling side effect or an infection, check with a doctor.) 

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.

The flu is not just an uncomfortable illness; it's also potentially deadly. From late 2019 into early 2020, up to 56 million cases of the flu were reported in the United States, according to the Centers for Disease Control (CDC), with somewhere between 24,000 and 62,000 deaths.

That's why the flu shot is recommended every year by doctors. Inoculation against influenza can prevent you from falling ill with the flu, reduce symptoms if you do catch it, and protect others through herd immunity, according to Bustle.

But you might be wary of side effects of the shot, including the feeling of fatigue that some people report. According to experts, however, it's a normal reaction and, while bothersome, is nothing to fear. So please, don't let the possibility of feeling a little more tired than usual stop you from getting the flu shot when flu season rolls around.

You'll probably only feel tired for a day or so

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Dr. Gustavo Ferrer of the Cleveland Clinic Florida Cough Center told Bustle that the tiredness some people feel is simply the body's defenses gearing up to protect you. "The symptoms are the result of the antibodies produced by our body in order to build up an immune response. In essence, a foreign substance (dead virus) ​entering our body that our defenses recognize and respond with fatigue, tiredness, low-grade fever, and lousiness," he said. Fatigue should pass within a day or so and should not be harmful.

According to Dr. Ferrer, resting following the shot is key to fighting the feeling of tiredness. "This is the time to rest. Don't push through. You need time to restore your energy," he said. So, take a nap on the couch or curl up in bed and get some much sleep. You'll feel better soon enough.

What else might you feel when you get the flu shot?

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Side effects from the flu shot can include things like soreness or redness at the site of injection, fever, headache, muscle aches, and nausea, according to the CDC. For most people, these pass within 24 to 48 hours and don't causes issues. Some people might feel dizzy or faint upon receiving the shot, which is usually a reaction to the injection itself.

A few symptoms might be indicative of an allergic reaction, however, and should be taken seriously. These include problems breathing, wheezing or hoarseness, swelling near the eyes or lips, hives, weakness, paleness, dizziness, and a fast heart rate. If you notice any of these symptoms, call your doctor or, depending on the severity, 911.

The flu shot is safe for pregnant women. People with a rare condition called Guillain-Barré syndrome are not advised to get the flu shot, along with anyone with a severe egg allergy. And if you're feeling ill or under the weather for any reason, postpone the shot until you feel better. 

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