The vaccine helps prevent illness–but what if you're already under the weather?

Sarah Klein
October 18, 2017

You penciled in some time to stop by the pharmacy or your doctor's office for your annual flu shot, and then–why can't anything go right?–you came down with a bug. Should you still get the flu shot if you're sick?

Depends on your symptoms, says Aidtya Gaur, MD, associate faculty member in the infectious diseases department at St. Jude Children's Research Hospital in Memphis, Tennessee. "Typically someone with a mild illness can be given a flu shot, but if it's a moderate or severe illness, vaccination is postponed until the person recovers."

If you're the type to put off getting your shot, don't let the sniffles be another excuse. "A mild illness is not a contraindication to getting the flu shot, and delaying it can potentially result in a missed opportunity for vaccination and related protection against flu," Dr. Gaur says.

RELATED: Here's Where You Can Get a Free Flu Shot This Fall

If your illness is more severe, you should check in with your doctor before getting vaccinated at work or a local pharmacy. "In someone who is moderately to severely ill, the healthcare provider may delay giving the flu shot to avoid confusing signs and symptoms of their illness with side effects of the vaccine," Dr. Gaur says. Some people experience muscle soreness, headaches, and fever after the flu shot. If you already have those symptoms, you won't be able to tell if you're having a reaction to the vaccine.

Speaking of those flu-shot reactions: If you do notice flu-like symptoms after getting the shot, it's not because the vaccine gave you the flu. Those are actually common side effects of any injection, according to the Centers for Disease Control and Prevention (CDC). The vaccine cannot give you the flu, promise.

If you get sick in the first few days after your shot, it's possible you caught the virus before your body had time to form antibodies to the vaccine. (That takes about two weeks.)

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While the vaccine doesn't offer 100% protection from the flu, it is still "the first and best way" to protect yourself, according to the CDC. Aside from cutting your chances of catching the bug, it also reduces your likelihood of developing life-threatening side effects of the flu if you do get sick.

Plus, the more people who get vaccinated, the lower the chances of the virus spreading to vulnerable folks like older adults and babies who could be in serious trouble if they get the flu. Simply washing your hands on the reg, while important, can't guarantee all that.