Are you avoiding the flu shot this year? If so, you're not alone.

Consumer Reports found that 48 percent of people did not plan to get vaccinated in 2008. A Harvard Medical School study found that over a decade, 56 percent of adolescents at risk of serious complications skipped the needle, too.

Why do people opt out of a vaccine that could potential save their lives, or at least keep them on their feet and out of bed?

Why Not Get The Shot?

Those surveyed in the Consumer Reports Health Study listed reasons ranging from fear to cost. The most common responses were that people wanted to build up their immune systems naturally, that they don't get sick any way, that they or someone they know has gotten sick from the vaccine and they're worried about the side effects.

Those reasons are shared by many Americans.

"I never really get the flu, so I don't feel the need to get a flu shot," Jamie Duklas of Denver said. "Plus, I don't really think that the flu shot necessarily prevents you from getting the flu. And who really wants to get a shot for nothing?"

Dr. Donald Deye, a physician at an Allina Medical Clinic in Cambridge, Minn., said some people don't even have specific reasons, they just don't want it.

"A patient this morning told me, 'I don't really know why I don't want it, I just don't," Deye said.

Reasons Don't Match Facts

While the reasons for not getting the flu shot are common, they are not entirely accurate.

For those hoping to build up immunity by not getting the vaccine, Deye recommends they rethink their strategy.

"That's the whole reason to get the vaccine, to build up immunity," Deye said. "If you're not getting the vaccine, you're leaving your immune system naked and exposed."

Vaccines teach the body to develop defenses to viruses by exposing it to weakened forms of invaders.

Deye said it is dfficult to build up immunity to the flu because the viruses in circulation change every year, meaning any immunity you do build up only lasts for a short amount of time. That's why the Center for Disease Control and Prevention recommends people receive the vaccine every year. The CDC changes the viruses in the vaccine each year based on scientific estimations about which strains of the virus pose a threat that year.

Deye said 2008's flu vaccine is using three different virus strains from last year, meaning it is even more important to get a shot this season.

For those who claim they don't need a shot because they don't get sick, medical resources point out that not everyone can avoid the virus.

"All of us don't get sick until we actually do," said Dr. William Marshall, a doctor of infectious disease at the Mayo Clinic.

Protect Others

Marshall also added that getting the flu vaccine not only protects you from the flu, but it also protects those around you -- including at-risk patients for whom getting the flu could be dangerous. Some of those Marshall listed as being at-risk are people who suffer from chronic heart, lung and kidney conditions; pregnant women; people whose immunity has been compromised by other illnesses; babies and the elderly.

During flu season, it can be hard for at-risk patients to avoid the infection. HealthNews.com reported that hundreds of thousands of people get the flu each year. If you're wondering how many people in your area are infected with the virus, you can check out Google's flu trends tracker The Web site allows users to click on their state and see their area's level of flu activity.

Those who avoid the shot because they're afraid they'll get the flu from the vaccine should stop worrying, the CDC says. In a release, the organization said the flu shot isn't a live virus, so you can't actually contract the illness from the vaccine. Deye said sometimes patients happen to come down with a cold around the time they receive their flu shot, which can lead some patients to attribute the symptoms to the shot.

There are potential side effects from the shot, but most of them are minor. According to the CDC, some of the most common side effects that may occur are soreness; redness or swelling where the shot was injected; a low-grade fever; and aches.

The CDC's Web site said that on rare occasions, some serious problems can occur, such as severe allergic reactions. The CDC warns that those who suffer from severe allergies from chicken or eggs should not receive the flu shot, because eggs are used to grow the samples.