I agree with Peg M and MommaL completely. Over 30,000 Americans every year die from the flu (mostly the elderly and very young), and thousands more are hospitalized with complications. Getting vaccinated with the flu shot is far, far safer than getting the flu. Very, very rarely does the flu shot have serious side effects. The reason that medical professionals encourage us to get the flu shot is because it is far riskier to get the flu than to get the vaccination against it. The flu shot has been available to people since 1976. It is well proved, and has no long-term side effects. It is made the same way other vaccines are.
If you are concerned with preservatives, the preservative free (mercury free) shot is easy to find. I called Las Vegas pharmacies like CVS and Wallgreens and found the preservative free version in minutes. My family was able to get preservative free flu shots earlier this month.
Additionally, you are right about reading that the flu shot is dangerous - there is lots of anti-flu vaccination "information" on the internet. But the sources for these websites are dubious - along the same lines as the websites that claim Barack Obama was born in Africa and the United States Government was responsible for the attacks on 9/11. I had a woman tell me recently that the flu shot was a plot by the United Nations to cause women to become infertile. She teaches anti-vaccination courses in Las Vegas.
So, please, please, please think critically about what you read on certain websites. I find the most reliable information comes from trusted sources like the websites of the Harvard Medical School, the Mayo Clinic and the Centers for Desease Control:
http://www.health.harvard.edu/topic/flu-resource-center
http://www.cdc.gov/flu/about/qa/flushot.htm#whatare
http://www.mayoclinic.com/health/flu-shots/ID00017
Last, don't rely on others' personal experiences. Medical professionals base their findings on science, statistics and an overview on public health. People who claim that nutrition alone will protect you from the flu, or that the flu makes your immune system stronger, are not necessarily guided by science. (http://www.health.harvard.edu/flu-resource-center/how-to-...)
-J.
P.S. One last thing to consider... By getting the flu shot, and thus not spreading the flu around, you are helping people who cannot get the flu shot because they are too young, or immunocompromised, stay healthy. You may even save a life.