Should You Get a Flu Shot If You’re Sick? Doctors Explain.
IT’S OFFICIALLY FLU SEASON. That means that if you haven't done this already, it’s a good time to get your flu shot.
With the flu already circulating, as well as Covid, colds, and other viruses, you may wonder if you can get a flu shot if you’re not feeling well. Or if you should hold off on getting vaccinated until your symptoms subside.
“Flu shots can be effective when you are sick, but it depends on how sick you are,” says Jay Lee, M.D., a member of the American Academy of Family Physicians board of directors and medical director of Integrated Health Partners of Southern California.
However, Dr. Lee says that deciding when to get a flu shot should hinge on how you’re feeling and whether you have a fever. When in doubt, talk to your doctor before getting vaccinated.
The Centers for Disease Control and Prevention (CDC) recommends that everyone six months old and older get a flu vaccine, unless they have an allergy to the vaccine. It can reduce your risk of getting the flu by 40 percent to 60 percent, according to the American Medical Association.
While it’s usually fine to get your flu shot when you’re sick, it's not going to cause you harm, says Tara Vijayan, M.D., associate professor in the Division of Infectious Diseases at the University of California, Los Angeles. But you may feel extra lousy if your symptoms comingle with any vaccine side effects—like headaches, muscle aches, low-grade fever, or nausea, says
There are a few other things to know about getting a flu shot when you’re sick, according to doctors:
Can you get a flu shot when you’re sick?
The CDC says people with a minor illness, like a cold, can go ahead and get vaccinated. But, if you’re moderately or severely ill, it’s a good idea to wait until you recover.
“With a mild illness, there should not be any issue with your body’s response to the flu vaccine,” says Shivanjali Shankaran, M.D., an infectious disease physician and associate professor at RUSH Medical College in Chicago. “In a much sicker patient, there is a possibility that they won’t respond as well to the vaccine.”
If you have a moderate or severe illness, your immune system might be taxed, and the antibody response to the vaccine won’t be strong, Dr. Lee says.
And, if you have a fever above 100.4 degrees Fahrenheit or can’t keep food or water down, he suggests waiting until you feel better to get the flu shot.
If you have Covid, Dr. Shankaran recommends waiting until you recover to get a flu vaccine. You also don’t want to risk exposing others to the virus when you’re getting the shot.
Should you get a flu shot if you have a fever?
Whenever you have a fever above 100.4 degrees F, it’s best to wait until your fever goes away to get a flu vaccine, Dr. Lee says, “so your immune system is able to mount a stronger antibody response.”
Basically, you might not respond “as robustly to the vaccine” as you would if you were feeling better, Dr. Shankaran says.
Some people also may develop a fever as a vaccine side effect, she adds. “If you take the vaccine while you are already having a fever, it will be hard to identify the real cause of the fever.”
Running a fever could also mean your illness is contagious, Dr. Vijayan says. So you risk transmitting your illness to the health workers administering the shot or others around you.
Can you get a flu shot if you’re taking cold medicine?
Most medications won’t affect your immune response to a flu shot, Dr. Lee says. However, he suggests avoiding taking anti-inflammatory medications, like ibuprofen or prednisone, before getting a flu vaccine, as they could potentially blunt your immune response.
Will the flu shot make you sick?
A common myth is that the flu shot will give you the flu. But, it's not true, Dr. Vijayan emphasizes.
Injectable flu shots don’t contain any live flu virus, she says. Any side effects to the shot, like a low-grade fever, body aches, headaches, and others, are your body’s immune response to the vaccine.
“So that when you do actually see the live flu virus, you’ll be less likely to get it, and if you do get it, you’re less likely to have a severe infection from it,” Dr. Vijayan says.
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