Myth busters: Common misconceptions of the flu shot explained

For the entire month of October, UT Southwestern’s Occupational Health department will administer free flu vaccines to employees in various locations across campus. Check out the flu kiosk schedule on My UTSW and find out how to become compliant. Employees enrolled in the UT SELECT and UT CONNET medical plans can have the vaccine covered at 100 percent as part of preventive care services, if they choose to be vaccinated elsewhere (within the provider network).

Aside from being a no-cost service, the flu vaccine is beneficial to maintaining personal health and can even save your life. To help clear the air of common misconceptions about the flu shot, the Occupational Health team took time to dispel myths and shed light on how this vaccine carries more pros than cons and should be a part of your annual health to-do list.

Just how effective is this year’s flu shot at preventing the flu?

According to the Centers for Disease Control and Prevention (CDC), the flu vaccine reduces the odds of getting the flu by about 60 percent, but that number varies from year to year and among different groups of people.

Can getting the flu shot itself make you sick? Why or why not?

No, flu vaccines cannot cause the flu illness. The flu shot uses an inactivated (killed) virus, which is not infectious.

Can I still contract the flu if I have the shot? If so, how common is this?

It’s possible, but unlikely. These are some reasons you may get flu symptoms:

  • One reason is that some people can become ill from other respiratory viruses besides flu, such as rhinoviruses. Rhinoviruses are associated with the common cold, cause symptoms similar to flu, and also spread and cause illness during the flu season. The flu vaccine only protects against influenza, not other illnesses.
  • Another explanation is that it is possible to be exposed to influenza viruses, which cause the flu, shortly before getting vaccinated or during the two-week period after vaccination that it takes the body to develop immune protection. This exposure may result in a person becoming ill with flu before protection from the vaccine takes effect.
  • A third reason why some people may experience flu-like symptoms despite getting vaccinated is that they may have been exposed to a flu virus that is very different from the viruses the vaccine is designed to protect against. The ability of a flu vaccine to protect a person depends largely on the similarity or “match” between the viruses selected to make the vaccine and those spreading and causing illness.

Is there mercury in the flu vaccine, and if so, is it safe?

Thimerosal is a mercury-containing compound that prevents the growth of dangerous bacteria and fungus. It is used as a preservative for flu vaccines in multi-dose vials, to keep the vaccine free from contamination. We do not use multi-dose vials, so there is no thimerosal/mercury in our single dose vials.

If I decide against getting the flu shot, what else can I do to avoid getting sick?

  1. Cover coughs and sneezes
  2. Avoid touching your eyes, nose, and mouth
  3. Wash your hands often
  4. Limit contact with family members who are ill
  5. Clean your home
  6. Practice healthy habits

What do the latest studies show regarding flu shot effectiveness?

There are no current studies for this year’s vaccine, but unlike other vaccines, the flu vaccine is often updated each season to protect against what researchers believe will be the dominant strains of the flu that year. Predictions are based on worldwide monitoring of viruses. While predictions are generally accurate, they aren't foolproof. The effectiveness of the flu vaccine in a given year depends on their accuracy.

Are there certain patient groups in particular that should get the shot?

  • Children aged 6 months through 4 years (59 months)
  • People aged 50 years and older
  • People with chronic lung disease (including asthma), heart disease (except hypertension), and kidney, liver, neurologic, blood, or metabolic disorders (including diabetes mellitus)
  • People who are immunosuppressed due to any cause (including immunosuppression caused by medications or by Human Immunodeficiency Virus (HIV) infection)
  • Women who are or will be pregnant during the influenza season and women up to two weeks after delivery
  • People who are aged 6 months through 18 years who are receiving aspirin or salicylate-containing medications and who therefore might be at risk for experiencing Reye syndrome after influenza virus infection
  • People who are residents of nursing homes and other chronic-care facilities
  • American Indians/Alaska Natives
  • People with extreme obesity (body-mass index (BMI) is 40 or greater)
  • Among adults, complications, hospitalizations, and deaths due to influenza are generally most common among those 65 years old and over

Are there alternatives to a shot?

There is a nasal spray vaccine possibly available through your primary care physician. The nasal spray vaccine is approved for use in people 2 years through 49 years of age. It is an option for healthy, non-pregnant people in this age group.

Overall, do you recommend getting the flu shot and why or why not?

Yes, the flu vaccine prevents millions of illnesses and flu-related doctors’ visits each year. It also:

  • Can reduce the risk of flu-associated hospitalizations for children, working age adults, and older adults
  • Is an important preventative tool for people with chronic health conditions
  • Helps protect women during and after pregnancy
  • Can be lifesaving in children and reduce the severity of illness in people who get vaccinated but still get sick
  • May protect people around you such as babies, older people, and people with chronic medical conditions