Every year, people protect themselves from influenza, or the flu, by getting the flu vaccine. This vaccine, which typically comes as a shot or nasal spray, can reduce your chances of getting the flu by as much as 60 percent.
Any side effects you may have from the flu shot are typically mild. However, in rare cases, they can be severe. Before you get your flu shot, you may want to know what you might expect. Read on to learn about common and rare side effects of the flu shot as well as how to reduce these effects.
Common side effects
The more common side effects of the flu shot are mild. They’re the same in adults, children, and babies.
Reaction at the injection site
The most common side effect of the flu shot is a reaction at the injection site, which is typically on the upper arm. After the shot is administered, you may have soreness, redness, warmth, and in some cases, slight swelling. These effects usually last less than two days. To help reduce discomfort, try taking some ibuprofen before getting your shot.
Headache and other aches and pains
After your shot, you might have headaches or some achiness and pain in the muscles throughout your body. This also usually happens on the first day and goes away within two days. Taking pain relievers such as ibuprofen can help ease your discomfort.
Dizziness or fainting
Some people experience dizziness or fainting with the flu shot. These effects should not last longer than a day or two. If you tend to get dizzy or faint when getting a shot, be sure to tell the healthcare provider before they give you the flu shot. You can also try sitting for a while after you receive the shot and having a snack before or after the shot.
A fever of 101°F or less is a common side effect of the shot. A slight fever is considered a mild side effect, and it should go away within a day or two. If the fever bothers you, you can take ibuprofen or acetaminophen.
Serious side effects
Serious side effects are rare with the flu shot, but they can include:
A fever greater than 101°F is not common. If you’re concerned about a high fever, call your doctor.
Severe allergic reactions
Rarely, the flu vaccine can cause a severe allergic reaction. Severe allergic reactions usually happen within a few hours of receiving the vaccine. Symptoms include:
- trouble breathing
- fast heart rate
If you have any of these symptoms, call your doctor right away. If they’re severe, call 911 or go to the nearest emergency room.
Guillain-Barré syndrome (GBS)
In very rare cases, some people who have received the flu vaccine have experienced Guillain-Barré syndrome (GBS), a neurologic condition that causes weakness and paralysis throughout your body. However, it’s not clear if the flu vaccine is the actual cause of GBS in these cases.
GBS is more likely to occur in people who’ve had GBS in the past, so be sure to tell your doctor if you have a history of this condition. That said, having GBS in the past does not always mean you can’t receive the flu vaccine. Talk to your doctor to find out if the flu vaccine is safe for you.
Call your doctor right away if you have symptoms of GBS after receiving the flu shot.
The flu shot is typically recommended for everyone six months of age or older. Anyone at risk of serious complications from the flu should also receive the flu shot. These include pregnant women, people older than 65 years, and people with chronic diseases as well as their caregivers.
The shot is not recommended for people who:
- have had an allergic reaction to the flu shot in the past
- have a severe allergy to eggs
- are currently sick with a fever
The flu shot is a safe, effective treatment with few side effects. Still, if you’re concerned about side effects, you can talk to your doctor or pharmacist. They can help you decide if a flu shot is right for you. Questions you may ask include:
- Is getting a flu shot a good idea for me?
- Am I at risk of serious complications from the flu?
- Am I at high risk of side effects from the flu shot?