It's important to get a flu shot—and here's why you shouldn't believe the dangerous myth that the flu shot is poisonous. 

By Stacey Leasca
Updated October 09, 2018

Flu season is officially here. In fact, the flu season has already been here for a few weeks. And that means you’re already late on getting your flu shot.

But, don’t worry, you a little time left. Ideally you should get a flu vaccine "before flu begins spreading in your community," according to the Centers for Disease Control and Prevention. This translates to getting the flu shot by the end of October at the latest (know that if you get busy and go past that timeframe, getting the flu shot late is better than never).

If fears about the flu shot are holding you back, know this: There's a dangerous myth that the flu vaccine is “poison.” Read on for why you shouldn't believe it.

What’s in the flu vaccine?

We’ll admit it. The list of ingredients inside the flu vaccine does sound a little scary, but according to the Centers for Disease Control, they are nothing to worry about.

“Vaccines contain ingredients, called antigens, which cause the body to develop immunity,” the organization explained. “Vaccines also contain very small amounts of other ingredients. All ingredients either help make the vaccine, or ensure the vaccine is safe and effective.” Here’s what’s inside:

Preservatives: The CDC lists preservatives on the ingredients, which help “prevent contamination.” One of those preservatives can be mercury, which in large doses can be toxic. However, the CDC explained, “There is no evidence that the small amounts of thimerosal in flu vaccines cause any harm, except for minor reactions like redness and swelling at the injection site.” It added that while there is no evidence suggesting that there are safety concerns with thimerosal, “vaccine manufacturers have stopped using it as a precautionary measure. Flu vaccines that do not contain thimerosal are available (in single-dose vials).”

Adjuvants: Next, it lists adjuvants like Aluminum salts, which “help stimulate the body’s response to the antigens.”

Stabilizers: The CDC also lists stabilizers like sugar to “keep the vaccine potent during transportation and storage.” These help keep the vaccine working even when exposed to harsh conditions such as high heat and light.

Residual cell culture: Also on the list of ingredients is residual cell culture, like egg protein, to “grow enough of the virus or bacteria to make the vaccine.” Note: If you have an egg allergy there are alternative flu shots which do not contain egg protein.

Inactive ingredients: There are inactive ingredients like Formaldehyde to “kill viruses or inactivate toxins during the manufacturing process.”

Residual antibiotics: And finally, residual antibiotics like neomycin to “prevent contamination by bacteria during the vaccine manufacturing process.”

What’s more dangerous—the ingredients in the vaccine or getting the flu?

Potential flu vaccine side effects can include soreness, redness, or swelling where the shot was given, a low-grade fever, and aches, according to the CDC. All of these side effects from the flu shot should be mild and short-lasting. You cannot, in fact, get sick from the flu shot itself.

The CDC does note there is a connection between the flu shot and Guillain-Barré syndrome, a rare disorder in which a person’s own immune system damages their nerve cells, causing muscle weakness and sometimes paralysis, which often resolves in a few days to weeks. But it importantly adds that this is extremely rare.

On the other hand, an estimated 200,000 Americans are hospitalized with the flu each year and 36,000 people die from contracting the virus.

Who should get a flu shot anyway?

According to the Mayo Clinic, the flu shot is highly recommended for susceptible groups of people including children, the elderly, pregnant women, and those suffering from chronic illnesses. Babies under 6 months old and anyone with a life-threatening allergy to the ingredients in the flu shot should not get vaccinated. Make sure to talk to your doctor about your risks before getting the shot.