Can you have an allergic reaction to the flu shot? It's very rare, but those with egg allergies may be at risk

• An allergic reaction to the flu shot is incredibly rare, but people with egg allergies may be slightly at risk.
• Signs of an allergic reaction to the flu shot include difficulty breathing, hives, facial swelling, paleness, and weakness.
• This article was reviewed by Jason R. McKnight, MD, MS, a family medicine physician and clinical assistant professor at Texas A&M College of Medicine.

The flu shot is the best defense that we have to protect ourselves and others from getting sick with the influenza virus. Every year, new flu shots are developed that will protect against multiple strains of the flu. The CDC recommends that everybody over the age of 6 months old get the flu shot, with only a few rare exceptions.

Luckily, allergic reactions to the flu shot are extremely uncommon, leaving little reason for us to avoid getting the flu shot, unless your doctor specifically advises against it for you. For example, if you have an egg allergy, you might need to take certain precautions and discuss the shot with your doctor.

Here's what you need to know about allergic reactions to the flu shot and whether you may be at risk.

Signs of an allergic reaction to the flu shot

The risk of having a severe allergic reaction to any vaccine, including the flu shot, is 1.3 in a million. People with an allergy to eggs are most at risk of having a severe allergic reaction, but you may have a reaction to other components of the vaccine, such as preservatives.

However, a preservative allergy is even rarer, and should not deter you from getting the flu shot, says Ryan Steele, DO, board-certified allergist-immunologist and internist at Yale Medicine.

Once you get your flu shot, you may want to monitor your reaction. According to the CDC, some signs of an allergic reaction to the flu shot are:

• Facial swelling around eyes and mouth
• Feeling weak
• Dizziness
• Appearing pale
• Fast heartbeat
• Hives
• Difficulty breathing

If you experience these symptoms, contact a healthcare provider immediately.

Egg allergy and the flu shot

The most common reason for an intense allergic reaction to the flu shot is an egg allergy, says Steele. Though there are no eggs in the active component of the vaccine, the shot and nasal spray are manufactured with small amounts of egg protein.

But just because you are allergic to eggs doesn't mean that you should avoid the flu shot entirely. The CDC says that you should still get the flu shot at your local clinic if you:

• Have some egg allergy symptoms, but you can eat lightly cooked eggs, such as scrambled eggs, without having a reaction.
• Have only gotten hives after eating eggs, without experiencing any other symptoms.

You should get the vaccine under the careful supervision of a healthcare provider in a medical setting if you:

• Have a serious reaction to eating eggs, such as respiratory distress, lightheadedness, swelling under the skin (angioedema), or recurrent episodes of vomiting.
• Have required an EpiPen or emergency medical help after eating eggs.

You should only avoid the flu vaccine altogether if you have previously had a severe reaction to the flu shot itself.

Additionally, there are egg-free options of the flu shot for those with egg allergies, to be extra safe. For the 2020-2021 flu season, there are two egg-free vaccines: Flublok Quadrivalent and Flucelvax Quadrivalent. These are the safest options for someone with an egg allergy, so contact your local clinic to see if they are available.

Guillain-Barré syndrome and the flu shot

It is a myth that Guillain-Barré syndrome (GBS) is a common reaction to the flu shot. In reality, there are only one to two cases of GBS per million flu shots administered.

GBS causes your immune system to attack nerves in your own body, resulting in symptoms like tingling or numbness that start in the lower body and escalate. This has the potential to result in paralysis, but most people can recover from GBS and live life normally.

But once again, GBS is not a legitimate concern from getting the flu shot, and you'll be better protected against it if you get vaccinated.

"You are more likely to get [GBS] from the flu itself rather than the vaccination," says Steele.

The bottom line

The benefits of getting the flu shot greatly outweigh the risks. If you don't get a flu shot, your chances of becoming seriously ill from the flu are much higher than your chances of having an allergic reaction to the vaccination.

"The seasonal flu vaccine is one of the safest and easiest things you can do for you and your family's health, particularly this flu season," says Steele.

If you have personal concerns about the flu shot and any allergies, consult your doctor.

Related articles from Health Reference:

• How to prevent the flu, according to doctors
• Yes, the flu is contagious. Here's when you're most likely to spread the virus
• You can't get the flu from the flu shot, but there are side effects
• How long the flu should last and when you should see a doctor
• The flu vaccine is not 100% effective but you should still get it every year