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Debunking the flu shot myths

September 17, 2012

You may have heard some of these concerns about the flu shot, but are they really true or merely common misperceptions?

“I got the flu from my flu shot.”

MYTH. The flu shot is an inactivated vaccine, which means that it is made of killed influenza virus. Sometimes people may have picked up another type of virus that produced mild symptoms shortly after they received their flu shot, and they may assume that because they are “sick,” then they have the flu.

However, if you got your flu shot today and then somebody infected with influenza virus happens to sneeze or cough on you, then you may become infected with the flu because your body hasn’t had enough time to develop enough antibodies from the vaccine. Influenza seasons can be unpredictable (remember the swine flu or H1N1 influenza pandemic in 2009?), and can start as early as October. Since it takes about 2 weeks after vaccination for antibodies to develop to protect you from the flu, the CDC recommends that you get your flu vaccine as soon as it is available in your community (even as early as August) before the flu season starts.

There is a type of flu vaccine that is a nasal spray. This vaccine is a live-attenuated influenza virus, which means that it does contain weakened influenza viruses. This type of vaccine should NOT be given to anybody who has a severely weakened immune system, because that person may actually become sick from influenza because it is a live-virus vaccine, as opposed to the shot, which is a killed virus. Children with a history of asthma or other chronic medical conditions should not receive the nasal spray flu vaccine. If you are considering the nasal spray flu vaccine for you or your children, please talk to your physician to determine if there are any reasons why your children should or should not receive this vaccine.

“I got a flu shot last year, so I don’t need another one this year.”

MYTH. A person’s immunity to the flu can drop by as much as 50% in 6-12 months after receiving a flu shot, so it’s best to get the vaccine every year for the best protection. We also need a flu vaccine every year because the flu viruses are constantly changing. Typically, we see new flu viruses every year, and they can even change during the same flu season. Before the flu season starts, experts analyze flu patterns and predict which viruses we will see in the upcoming season, and then build the vaccine to protect against the most likely flu viruses that we will see.

For the 2012-2013 season, the seasonal flu vaccine includes protection against three types of influenza:

  • An influenza A (H1N1) virus
  • An influenza A (H3N2) virus
  • An influenza B virus
Remember that the best way to protect against the flu is to get vaccinated every year. Even if the vaccine is not a “perfect” match, the antibodies made in response to one flu virus can sometimes provide protection against different but related influenza viruses.

“The flu doesn’t really make you that sick, so why should I get the flu shot?”

MYTH. The flu is a contagious respiratory illness that can make you or your child very sick. It can be mild or severe, and may even cause death. The symptoms are typically worse than the common cold. Most people who get the flu will recover in a few days or a couple of weeks, but some people may develop complications from the flu. These complications can include pneumonia or respiratory failure, and can lead to death. Children that have underlying medical conditions such as asthma may develop severe asthma attacks that can be triggered by the flu.

Flu symptoms include:

  • Fever
  • Chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue
  • Vomiting
  • Diarrhea
There are people who are at higher risk for developing severe complications from the flu: young children, pregnant women, people at any age with chronic medical conditions (such as asthma, diabetes, or heart disease), and people 65 years or older.

“Everybody should get the flu shot.”

MYTH. Everyone who is at least 6 months of age should get a flu vaccine this season. Special efforts should be made to vaccinate family members and household contacts of children younger than 5 years of age, or children with chronic medical conditions. Pregnant women and health-care personnel should also be immunized.

There are some people who should not get a flu vaccine before talking to their physician:

  • Anybody who has a severe (anaphylactic) reaction to chicken eggs
  • Anybody who has had a severe reaction to an influenza vaccination
  • Children under 6 months of age (the flu vaccine is not approved for this age group)
  • People who currently have a moderate-to-severe illness with fever (they should wait until they recover to get vaccinated)
  • People with a history of Guillain-Barré syndrome, or severe paralytic illness
The seasonal flu vaccine is the best protection against influenza infection, and your pediatrician or family physician can provide information that will help you make the best decision for you and your family.

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