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When you receive a flu vaccine, your body thinks it has contracted a mild case of the illness, and it builds immunity against the virus. If you are exposed later to virus from a person with the flu, you may not get sick at all. Flu viruses may change from year to year and protection from a flu vaccine wears off over time, so doctors recommend getting a flu vaccine every year.
The flu shot prevents you from getting the flu, or influenza, by training your body's immune system to both recognize and fight the flu. After getting the flu shot, your body needs about two weeks to create this immune response. That is why it is important to get the flu shot at the beginning of the flu season. If you wait to get the shot until the flu is common in the community, you may be exposed to the flu before your body can create the desired immune response.
Preventive Medicine Specialist Dr. David Katz explains how the flu shot prevents you from getting the flu. Watch Dr. Katz's video for information on preventive medicine and overall wellness.
The flu vaccine protects against the three main flu strains that research indicates will cause the most illness during the flu season. For the 2011-2012 flu season the influenza vaccine strains are:
- an A/California/7/2009 (H1N1)-like virus;
- an A/Perth/16/2009 (H3N2)-like virus; and
- a B/Brisbane/60/2008-like virus.
The 2011-2012 influenza vaccine can protect you from getting sick from these three viruses, or it can make your illness milder if you get a related but different influenza virus strain.
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