LilacLuv, The flu vaccine is used as a tool to prevent the widespread contamination of the virus. There are two schools of thought for use in immunosuppressed patients. Each one has a legitimate basis. First you have to understand that the flu shot DOES NOT GIVE YOU THE FLU. It takes about 10-14 days for the vaccine to work. If someone developes the flu after the vaccine is given than they were exposed to the flu before the shot was given and the vaccine has not had time to work yet.
The first school believes an immunosuppressed patient should recieve the vaccine to prevent the ravages of the influenza virus or at least minimize the virus' attacks on the body.
The second school believes that the vaccine itself may be too much for the immunosuppressed patient to tolerate as sometimes the vaccine will cause flu-like symptoms. If the patient is too immunosuppressed and they have symptoms it may be too much for the body to handle and they will become gravely ill and possibly even die.
Either way you should follow your Doctors advice. If you do not get vaccinated just follow good hygiene practices and avoid any public arena contact.
Flu vaccines are given yearly because the viruses mutate all the time. So last years vaccine will not be effective this year. I hope this helps a little.