Flu season is here again, making it important to do what you can to be prepared. According to doctors, the best way to protect yourself against the flu is to get a flu shot. But, while you’re booking your shot, it’s understandable to have questions about flu shot side effects.
Overall, doctors say that flu shot side effects are similar to what you can expect from pretty much any other vaccine. And, if you’ve been vaccinated against the flu in the past, the odds are high that you’ll have a similar reaction (if any) this time around as well.
Meet the experts: Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York; William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine
Of course, the vaccine is different each year to target the circulating strains. So, what are flu shot side effects for 2024? Infectious disease doctors explain.
What are flu shot side effects for 2024?
Doctors stress that the flu shot side effects aren’t usually something to stress over. “The side effects are usually minor,” if you have them at all, says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine.
According to the Centers for Disease Control and Prevention (CDC), the side effects may include:
Arm soreness Redness around the injection site Arm swelling Headache Fever Nausea Muscle aches
The shot may also raise the risk of fainting in people who are prone to passing out from a shot, per the CDC. Still, “most people get a sore arm and that’s it,” Dr. Schaffner says.
When will flu shot side effects start?
It you have flu shot side effects at all, they will likely start eight to 12 hours after your shot, says Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York.
“You can plan it out in anticipation of having side effects, so you don’t have to be working or doing something important,” he says. With that, he suggests planning to get your shot on a Friday afternoon, if you are off on weekends.
How long do flu shot side effects last?
Everyone is different, but flu shot side effects will usually last a day or two, Dr. Russo says. (Again, if you have them at all.)
Can the flu shot cause the flu?
No, the flu shot can’t cause the flu. The flu shot contains either an inactivated virus (which means it’s no longer infectious) or a particle that’s designed to look like a flu virus to your immune system, according to the CDC.
The nasal spray flu vaccine contains a live virus, but the viruses are changed so that they can’t give you the flu, per the CDC.
When should I get the flu shot?
The CDC suggests getting your flu shot by Halloween, but don’t panic if that doesn’t happen. Flu season is long, with some seasons stretching until May, so Dr. Russo says there’s value in still getting vaccinated if you can’t make the Halloween cut-off.
Can you take medication before your flu shot?
If you tend to feel yucky after your flu shot, it makes sense to at least wonder if it would help to take a medication like acetaminophen or ibuprofen before your shot. But Dr. Russo says that there’s “controversy” about this approach, noting that some people in the medical community think it may impact your immune system’s response to the vaccine.
“It’s not the best recommendation to take something in advance,” he says. To play it safe, Dr. Russo recommends that you “see how it goes” and then take an OTC medication if you think you need it.
Can you have an allergic reaction to the flu shot?
Yes, you can have an allergic reaction to the flu shot. “It’s relatively rare, though,” Dr. Russo says.
“If you’ve had an allergic reaction to the flu shot in the past, the best strategy is to see an allergist who can assess the nature of that reaction,” he says. “Then, you can have shared decision-making on whether you would be a good candidate.”
But Dr. Russo also points out that having flu shot side effects isn’t the same as having an allergic reaction. “Allergic reactions would be getting hives elsewhere, wheezing, shortness of breath, or a more severe reaction like anaphylaxis,” Dr. Russo says.
How to treat flu show side effects
Again, most people who have flu shot side effects only have a sore arm, if that. But some people will have things like muscle aches, headache, or flu-like symptoms. If you fall into this camp, Dr. Russo says that you’re fine to take an OTC pain reliever, like Tylenol or ibuprofen.
If you have arm pain, you can use a cool compress on the spot.
When to call a doctor about flu shot side effects
If you have constant pain, swelling, a severe rash, or symptoms of an allergic reaction, Dr. Russo says you should seek medical care.
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