What Are the Flu Shot Side Effects for the 2024-2025 Flu Season?

The CDC recommends that anyone over the age of 6 months should get the flu vaccine annually to help protect themselves and others from contracting the flu. One myth you may hear about getting the flu vaccine is that it can cause you to get the flu. This is not the case; the vaccine cannot give you the flu. However, it is possible to get sick with the flu even if you have been vaccinated (although you won’t know for sure unless you get a flu test). This can happen because:

• You may be exposed to a flu virus shortly before getting vaccinated or during the period that it takes the body to gain protection after getting vaccinated. This exposure may result in you becoming ill with the flu before the vaccine begins to protect you. About two weeks after vaccination, antibodies that provide protection develop in the body.
• You may be exposed to a flu virus that is not included in the seasonal flu vaccine. Many different flu viruses circulate every year. The flu vaccine is made to protect against the three or four flu viruses that research suggests will be most common.

For most patients, they will not experience any side effects from the flu vaccine. But like any medical product, vaccines may cause some mild side effects that typically go away within a day or two. Common side effects from the flu vaccine include:

• Headache
• Fatigue
• Cough
• Low fever
• Arm soreness, redness or swelling lasting a couple of days.

Fewer than 1 in a million people experience severe allergic reactions to the flu vaccine. If someone does have a severe allergic reaction, this would most likely happen within a few minutes of receiving the vaccine, which is why it is best to wait a few minutes at your doctor’s office after receiving any vaccine. Signs of an allergic reaction include:

• Difficulty breathing
• Hoarseness or wheezing
• Swelling around the eyes or lips
• Hives
• Paleness
• Weakness
• A fast heartbeat or dizziness

If you believe you are having a severe allergic reaction and you are not at your doctor’s office, call 911 and get to the nearest hospital.

Can you get the flu vaccine if you are allergic to eggs?

People who have experienced only hives after exposure to egg can get any licensed flu vaccine that is otherwise appropriate for their age and health.

People who have symptoms other than hives after exposure to eggs, such as angioedema (swelling that may occur in the face, tongue, larynx, abdomen or arms and legs), respiratory distress, lightheadedness or recurrent emesis; or who have needed epinephrine or another emergency medical intervention, can also get any licensed flu vaccine that is otherwise appropriate for their age and health. However, the vaccine should be given in a medical setting and be supervised by a health care provider who can recognize and manage severe allergic conditions. (Settings include hospitals, clinics, health departments and physician offices). For those with egg allergies, Ochsner will offer an egg-free flu vaccine.

Under very few rare cases will your physician recommend you not to get the flu vaccine. For most individuals, the flu vaccine is the best protection against contracting the flu, and it is quick and painless!

Editor's note - This blog was originally published on Oct. 29, 2020 and has since been updated.