Should you get the flu shot?

December 05, 2013
Get the flu shot

Every flu season, UC Irvine Health internist Dr. Emilie Chow finds herself repeating one thing: the flu vaccine does not cause the flu.

"Each year, that is our number one question," the primary care physician says.

It’s not the only misconception about the flu vaccine she encounters.

Some patients express a general fear of vaccines, believing that they cause autism. Others worry that vaccines overload the immune system and make it less effective at fighting infection. Often, says Chow, those beliefs are based on fears rather than scientific evidence.

Chow believes that full vaccination is the key to remaining in good health.

"I want all of our physicians and patients to be healthy, and flu vaccines can keep people healthier throughout the flu season," she says.

Seasonal flu vaccines become available in the fall and are usually offered until February or March.

Nasal vs. injected vaccine

Flu vaccines usually come in two forms:

  • Injectable vaccine, which contains no live virus.
  • Intranasal vaccine, which has a weakened version of the live virus, known as attenuated influenza.

Although both are safe, they do come with side effects.

The most common side effect of the injected vaccine is soreness at the injection site. The soreness can be caused by the immune system making protective antibodies in response to the vaccine, which is what helps the body fight flu.

The intranasal vaccine, which is only approved for use in healthy people between the ages of two and 49, can cause a runny nose and headache. If it is given to someone with a weakened immune system, side effects can be more severe: congestion, fever, cough, vomiting and diarrhea.

Vaccine myth busting

Despite what doctors say, the myth persists that the vaccine causes the flu.

In fact, some people do come down with a flu virus after being vaccinated. However, the vaccine is not the cause, says Chow.

There are several reasons why you may still become sick after being vaccinated.

  • The timing of the flu shot: Since the vaccine can take a few weeks to become effective, it will not protect you from the virus if you are exposed shortly after receiving a shot.
  • Another illness: You may become ill with something that resembles the flu, such as rhinovirus.
  • The type of vaccine: The flu shot protects against several viruses health experts/researchers have predicted to be the most common in a flu season. You can still become sick if you are exposed to a virus not included in the vaccine.
  • Ineffective vaccine: Although the vaccine works in the majority of people, the protection it offers can vary according to factors such as age and overall health. According to the Centers for Disease Control and Prevention, the virus works best in young, healthy adults and older children.

Chow has seen the effects of influenza, which can be serious. “People die of it,” she says, noting it can lead to complications such as pneumonia.

For that reason, she says, she urges everyone to get vaccinated.

“I want patients to get vaccinated. I'm passionate about it, because it has the potential to save lives.”

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