No, it will not give you the flu.
By Sarah Bradley
Definitely don’t mean to sound like your mom here, but…have you gotten your flu shot yet?
Just asking because, you know, the flu was super-deadly last year—an estimated 80,000 people died of the flu and its complications last winter, according to the Associated Press. (Just as a baseline, the flu can cause 12,000 deaths per year during a mild season, and up to 56,000 deaths per year during a severe bout, per the Centers for Disease Control and Prevention.)
But if you’re hesitant to get jabbed by a needle, I get it: The flu shot was kind of a crapshoot last year after a ton of people went under the needle but got the flu anyway because of a “vaccine mismatch,” according to a commentary in The New England Journal of Medicine.
Still, that doesn’t mean you should be thinking about skipping this year’s injection—which you should get by the end of October, suggests the CDC. (Flu season typically starts in October, peaks in December, and can stick around until May, so you want to be covered for all of it.)
FYI: The flu shot can’t actually give you the flu.
According to Amesh Adalja, M.D., a senior scholar at the Johns Hopkins Center for Health Security, the flu shot usually provides about a 65 percent protection rate against contracting the flu—and that number is nothing to sneeze at. (FYI: The effectiveness rate of last year’s flu shot? Just 36 percent, per the CDC.)
“Just because the vaccine isn’t 100 percent [effective] doesn’t mean it’s worthless,” says Adalja. “And even if you do get the flu, [if you’re vaccinated] you are much less likely to have a severe case requiring hospitalization, less likely to have major destruction to your life, and less likely to spread it.”
Plus, there’s some good news about the 2018-2019 flu shot: Researchers think it will be more successful than last year’s vaccine. According to the CDC, this year’s vaccines are a better match to circulating viruses than last year’s. TG, right? But still, there’s really no way yet to predict how bad this year’s flu will be, as the virus is always changing, per the CDC.
Another thing to note: Rumors of the shot’s many side effects are greatly exaggerated. It can’t actually give you the flu, and while there are some possible side effects, Adalja says most are rare.
Read through this list and then roll up your sleeve anyway, because flu season is coming and the vaccine is still your best defense.
- Shoulder soreness
If you receive the flu shot as an intramuscular injection (a.k.a. in your arm, typically), you have a 10 to 64 percent chance of experiencing some muscle soreness in your upper arm, according to the CDC.
That’s because the needle is injected directly into the muscle, causing microscopic damage to the cells, and is designed to cause an inflammatory immune system response. You can take OTC pain relievers while you wait for the soreness to fade, but if the pain is very noticeable or decreasing your mobility, Adalja recommends checking with your doctor..
- Redness or swelling at the injection site
Anytime you pierce the skin and put something into the body it can cause a topical reaction, says Adalja. This is just a sign that your immune system is activating.
But this redness and swelling where you get your shot is a common side effect that only typically lasts a few days. It’ll go away on its own, but if it’s really bugging you, you can take ibuprofen or acetominophen.
- Body aches
Any vaccine can cause body aches because of the immune system activation, says Adalja.
If you’re feeling sore in places other than your arm, it’s usually nothing to worry about, though Adalja notes that the flu shot does take two weeks to become fully effective—so your body aches could be a sign of the actual flu, since viral strains are probably circulating around the time you get the vaccine.
- Itching at the injection site or a full-body rash
This would signal an allergic reaction, but “it’s very rare to have an allergic reaction to the flu shot,” Adalja says. “There are lots of myths about egg allergies and the vaccine, but if you can eat scrambled eggs, you’re not going to have a problem with the flu shot.” And even if you have a confirmed egg allergy, you can likely still get the flu shot, per the CDC.
That said, if you experience severe itching at injection site, a rash all over your body, or signs of anaphylactic shock, seek immediate medical attention.
One thing to note: If you’ve had an allergic reaction to the flu shot in the past, you are among those few groups of people who the CDC recommends skip the flu shot.
You probably won’t get a fever because of the vaccine, but if you do, it should be low-grade (i.e. less than 101 degrees). If it’s higher than that, don’t blame your flu shot—you probably have a totally unrelated illness. “Remember that you’re getting the vaccine at the height of respiratory virus season,” says Adalja. “So you may have been incubating another virus [without knowing it].”
And once again for the people in the back: The flu shot cannot give you the flu. While some flu vaccines contain virus strains, they’re not live strains, so they can’t get you sick. Meanwhile some flu shots don’t contain the virus at all (they only contain a specific protein from the influenza virus), per the CDC.
- Dizziness or fainting
This is less a side effect of the vaccine itself and more a side effect of a needle phobia, says Adalja. If you think you might have a stress reaction or faint, give your healthcare provider a heads-up so they can make sure you stay seated after the shot to prevent injury.
- Guillain-Barre Syndrome
Guillain-Barre Syndrome (GBS) is an auto-immune disorder that’s triggered by a wide variety of things, from vaccines to viral infections.
GBS causes damage to the nervous system, resulting in symptoms like muscle weakness, numbness, difficulty walking or an odd gait, and even paralysis, says Adalja. While 70 percent of people fully recover from the disorder, the recovery period can range from weeks to even years, according to the National Institute of Neurological Disorders and Stroke.
But he also says the connection between GBS and the flu vaccine has been overhyped: “People should remember that influenza itself is much more likely to cause GBS than the vaccine.” And since no more than one or two cases per million people vaccinated will have this side effect, it’s better to take your (super small) chances with GBS than with one of the many common, severe complications which often come with the flu itself.