Will Getting The Flu Shot Actually Make You Sick?

Let us give it to you straight: Yes, you should probably get that flu shot you’ve been putting off. Around 80,000 Americans died and more than 900,000 were hospitalized for the flu or flu-related complications during the 2017-2018 flu season , according to the U.S. Centers for Disease Control and Prevention . (So, in other words, getting a flu shot is hardly a waste of your time.)

The flu, or influenza as doctors call it, is a contagious respiratory illness caused by strains of the flu virus. It can present in a number of ways, from mild to severe, leaving people with symptoms like body aches, a sore throat, coughing and headaches. In worst-case scenarios, it can sometimes result in death.

One of the simplest ways to protect yourself against the flu is with a quick vaccination. Typically, it takes barely any time out of your day, is cheap in cost or even free, and rarely has any lasting negative effects. Sort of a no-brainer, right?

“Getting a flu shot is one of the most important things that we can do to protect ourselves and those around us,” said Deborah Yokoe, a professor of clinical medicine and medical director of the University of California, San Francisco’s Hospital Epidemiology and Infection Control.

Despite the facts, many people still choose to steer clear of flu shots for a range of reasons. So allow us to clear up some of the confusion. Here’s what you need to know:

The flu shot isn’t going to give you the flu.

The rumors about this seem to be in endless circulation, but allow us to lay them to rest: The flu shot is not going to give you the flu.

“The flu shot is not a live virus, it is just pieces of virus, so it cannot give an infection,” said Wilbur Chen, an associate professor of medicine and chief of the adult clinical studies section at University of Maryland School of Medicine Center for Vaccine Development.

That said, it’s not unheard of to feel a bit off afterward. For one or two days, you might have soreness in the arm where the shot was injected, a low-grade fever or muscle aches. But these side effects are much less severe than getting the flu, Yokoe said. And if you happen to get really sick after getting a flu shot, it could just be a matter of timing.

“Sometimes people wrongly think that the flu shot made them sick because it takes two weeks for it to protect you, and during this time you can get the flu,” said Lynn Ramirez, an associate professor of pediatrics and medical director of UCSF Hospital Epidemiology and Infection Control. 

The flu shot won’t protect against all flu strains.

The flu shot works by causing your body to develop antibodies that protect you against the different strains of the flu virus that are present in that year’s vaccine. Each year’s flu shot is different and protects against three or four different strains of flu virus that researchers predict will be circulating heavily that year. The match is better some years than others, Chen said, but “even for a year with sub-optimal matching, getting an influenza vaccine is better than none at all.”

And if you do fall ill from the flu, even after a vaccination, the flu shot may make your illness less severe.

“Some people think that healthy people don’t need a flu vaccine, Ramirez said. “This is not true. People who are healthy can get the flu and become seriously ill and die.”

Getting the shot isn’t just about you.

While a flu shot is a huge step in the right direction when it comes to protecting your own health, the benefits extend beyond the personal. When you get a flu shot, you’re also helping to keep the people around you healthy, too.  

“[The flu shot] is really important to prevent you from spreading flu to other people who are at risk for serious flu illness and complications, including babies and young children, older people and people with certain chronic health conditions,” Yokoe said.

Now’s a good time to get your shot.

Flu season starts around the end of October, and the flu shot takes about two weeks to be effective so right now is a great time to get vaccinated. Even if you don’t get vaccinated at the start of the season, it’s still smart to get the shot at any time, given that flu season is long and can extend into early spring.

If you’re planning to get a flu shot but happen to be feeling a bit under the weather, hold off for another day. Most doctors would rather wait until a person recovers from a temporary illness before vaccination, Chen said.

You may have also heard that you don’t want to get your flu shot too early in the season. Chen explained that there is some evidence that the flu vaccine may wear off after about six months, which has some scientists concerned that people vaccinated as early as August and September may not have full protection. But it’s still better to get a shot early in the season than not at all, he added.

“The strongest argument is that any vaccination is better than no vaccination,” Chen said. “It is a much bigger problem to not be vaccinated than to have some minor level of waning immunity to vaccination.”

CORRECTION: A previous version of this story misstated the number of people hospitalized for the flu or flu-related complications during the 2017-2018 flu season.