What Are the Most Common Flu Shot Side Effects?

Here's everything you want to know about the potential, not-so-fun flu shot side effects, plus whether it's actually possible to get the flu from the vaccine.

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Everyone knows at least one person who's declared they'll never get another flu shot because they've had to suffer through nasty side effects from the vaccine. In fact, this desire to avoid flu shot side effects was the top reason that Americans decided to skip out on getting the jab in 2018, according to a NORC at the University of Chicago survey of more than 1,200 people.

If you're needle-averse, it might be tempting to hop on the anti-vax bandwagon, but there's also a lot to be gained from getting the shot each year — you know, like not contracting a flu virus and a reduced illness severity even if you do get sick, according to the Centers for Disease Control and Prevention. But if you're thinking about putting off this year's vaccine on account of potential flu shot side effects, here's what you should know — and why you should still consider getting the jab.

What are the side effects of the flu shot?

Yes, you can experience flu shot side effects, but in most cases they're NBD. "The most common side effects of the flu shot are local at the injection site," says Gustavo Ferrer, M.D., founder of the Cleveland Clinic Florida Cough Clinic. "People can have soreness, tenderness, and swelling." It's also possible that'll you'll feel sick afterward. "Small people can have flu-like symptoms such as low-grade fever, muscle aches, tiredness, and headaches that can last a couple of days," says Dr. Ferrer.

Typically, flu shot side effects will begin to be noticeable about six to 12 hours after getting the vaccine. And although the arm soreness, fever, chills, headache, and just general discomfort you may be experiencing can be irritating, these symptoms usually last no more than a couple of days, says Purvi Parikh, M.D., an adult and pediatric allergist and immunologist with Allergy & Asthma Network. And it's not a guarantee that you'll have any of these uncomfy reactions: Some folks might not experience any side effects from the vaccine, says Dr. Parikh.

Giving your body plenty of rest, staying hydrated (think: drinking about two liters of water a day), and taking Tylenol can help ease your flu shot side effects, says Dr. Parikh. But if your symptoms last more than a week or don't improve with counter medications, book an appointment with your doctor, she recommends.

Are there any long-term side effects of the flu shot?

Simply put, "no, there are not any long-term side effects," says Dr. Parikh.Still, it's possible to have severe flu shot side effects if you're allergic to a component of the vaccine — and these may cause lasting impacts, she says. Trouble breathing, swelling around the eyes or lips, hives, paleness, weakness, dizziness, or a rapid heartbeat are all signs of a severe allergic reaction, and these symptoms typically appear a few minutes to a few hours post-vax, according to the CDC. These reactions are "exceedingly rare," affecting about one in a million individuals, says Dr. Parikh. Regardless, "you should seek medical attention immediately if you are having a life-threatening allergic reaction with hives, wheezing, shortness of breath, dizziness, nausea, vomiting, or diarrhea," she says.

TL;DR: The gov agency advises people who know they have a severe, life-threatening allergy to the flu vaccine or any of the ingredients (such as egg, which is commonly involved in making the vaccine) in it to skip getting their jab.

What are the side effects of this year's flu shot?

Spoiler: This year's flu shot side effects are pretty similar to last year's — and all the years before that. Even though there's a new flu shot every season, as flu viruses are constantly changing, these possible side effects remain generally the same. Reminder: Each year, the Food and Drug Administration reviews the World Health Organization's research-based forecasts on the specific viruses that will be most common — and likely to cause illness — during the upcoming flu season. Using the organization's insight and recommendations, the FDA decides the four strains of influenza that the new flu shot should protect against. But regardless of the virus variation from year to year, the flu shot side effects really won't vary, say both Dr. Ferrer and Dr. Parikh.

Can the flu shot give you the flu?

While some people get flu-like symptoms from the flu shot, the idea that the shot can give you the flu is a misconception, says flu expert Norman Moore, Ph.D., director of infectious diseases scientific affairs for Abbott. "You cannot get the flu from a flu shot," he says. "The flu vaccine is made with either inactivated flu viruses that are not infectious or with a strain that is genetically engineered so it can't cause disease." The CDC backs this up: Flu vaccines given via needle are made with either inactivated (re: killed) viruses or with only a single protein from the flu virus, so they cannot cause flu illness. So while short-term flu shot side effects are a possibility, you don't have to worry about causing exactly what you were trying to avoid in the first place.

The main takeaway on flu shot side effects: For most people, the flu vaccine may just cause a a vaccination-site ouchie or headache. And considering the "side effects are not severe or permanent, and the risks of not getting the vaccine are far worse," says Dr. Parikh, a quick jab is definitely the better option.

Updated by Megan Falk
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