Allergic to one vaccine, allergic to all?

Dear Alice,

If I had a serious allergic reaction to the meningitis vaccine, will I be allergic to the flu shot?

Dear Reader,

Figuring out whether to take a shot at getting the flu shot? For the vast majority of people, vaccines are an effective and very low-risk way of preventing illness and disease spread. While side effects of vaccines are a common concern, thankfully, these serious reactions are uncommon. Allergic reactions usually occur as a response to components of the vaccine rather than the actual immunizing agent. Often, patients that are allergic to one vaccine will show no adverse reactions to others. Though no two vaccines are the same, people who have had an allergic reaction to one before — whether it was for meningitis or the flu — are strongly advised to discuss getting a new vaccine with a health care provider before making a decision. Speaking with them about each vaccine and their components can help determine if an allergic reaction is likely for you. 

For those who have experienced an immediate reaction to a previous immunization, as you experienced with the meningitis vaccine, it's helpful to identify the type of reaction that occurred. An expert medical provider, such as an allergist, may be able to identify the particular agent responsible for the allergic reaction given your symptoms and medical history. Knowing the cause of the reaction may be useful in avoiding vaccines with certain components listed on the package insert that you may be allergic to. While rare, adverse reactions to vaccines more commonly occur among people who:

  • Are allergic to eggs (the flu and yellow fever vaccines are grown in eggs)
  • Are allergic to gelatin or gelatin-containing products (common ingredient in flu vaccines)
  • Are allergic to latex (due to vials or syringes)
  • Had an allergic reaction to a previous flu shot
  • Had an allergic reaction to a previous vaccine
  • Have other severe allergies
  • Developed Guillain-Barré syndrome after receiving a flu vaccine

Reactions to vaccines are categorized as local, systemic, and severe. Local reactions such as redness or swelling at the injection site are the most common but also the least concerning as they often subside quickly. Common systemic reactions to a vaccine include a mild fever, chills, headache, and muscle aches. While these side effects may be a good sign that your body is starting to build up immunity against a disease, contact a health care provider if they persist long-term. Side effects may be uncomfortable at times but that doesn't mean it's an allergic reaction. If after vaccination you experience a severe allergic reaction characterized by difficulty breathing, swelling of the face or throat, fast heartbeat, dizziness, weakness, or a full-body rash it's crucial to seek immediate medical care. Because severe reactions usually occur instantaneously, medical professionals administering the vaccine would likely be equipped with sufficient training and medications on hand to counteract potential allergic reactions. It's wise to be mindful of these risks but also remember that these events are extremely rare. In most cases, getting vaccinated is safer than getting the diseases these vaccines prevent.

If you aren't feeling well on the day of vaccination or have experienced any of these conditions, talking with your health care provider can help you figure out whether a vaccine is appropriate for you. They may recommend alternative options, such as the nasal spray vaccine available for the flu, or provide you with a list of alternative precautions to take in order to stay healthy and flu-free this season. In the meantime, you may want to brush up on the way to wash your hands and check out the response in How can I boost my immune system? in the Go Ask Alice! General Health archives. You may also encourage the people in your life to get the flu shot if they're able. Even if it turns out that the vaccine isn't appropriate for you, then you'll have a reduced risk of catching the flu when you're around people with whom you spend the most time. 

Last updated Nov 26, 2021
Originally published Dec 18, 2009

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