Each year the Centers for Disease Control (CDC) encourages Americans to receive the flu vaccine to significantly reduce the chance of contracting the miserable illness that causes fever 100o F or higher, chills, muscle aches, cough, congestion, runny nose, headaches, sore throat, and fatigue. The flu is not just an annoyance: More than 200,000 people are hospitalized in the United States from flu complications each year. The flu also can be deadly. Over a period of 30 years, between 1976 and 2006, estimates of yearly flu-associated deaths in the United States range from a low of about 3,000 to a high of about 49,000 people during the most severe season.
Most people who skip the influenza vaccination every year because of myths: they will never get the flu; the flu isn't dangerous; the vaccination gives you the flu; I will notget terribly sick from the flu if I'm infected.
Of all these reasons, only the last is true -- and only for a certain group of people. For healthy young adults, it is unlikely that the flu will be deadly or dangerous enough to require hospitalization. But there is an extremely good reason to get vaccinated:
Receiving the flu vaccine does more than provide a very high rate of immunity to you, it affords your loved ones and your entire community reduced chances of getting the flu. The process of conferring immunity to those within a highly immunized population is called “herd” or community immunity. Even those who are not eligible for certain vaccines—such as infants, pregnant women, people allergic to eggs from which the vaccine is created, or immune-compromised individuals (AIDS, cancer) —get some protection because the spread of contagious disease is contained.
The principle of community immunity applies to control of a variety of contagious diseases, including influenza, measles, mumps, polio, and pneumococcal disease.
Reluctance to get a shot every year is part of the reason why national flu vaccination rates are so dismal -- about 40 percent of the country each year -- far below the 80 percent to 90 percent needed to achieve herd immunity and protect the most vulnerable in the population.
In the illustration (http://www.vaccines.gov/basics/protection/) the top box depicts a community in which no one is immunized and an outbreak occurs. In the middle box, some of the population is immunized but not enough to confer community immunity. In the bottom box, a critical portion of the population is immunized, protecting most community members.