I do not think the flu shot is necessary for healthy adults. There is no strong evidence which show the flu shot effective for healthy adults. Moreover, can the flu shot prevent flu shot sides effects? Some researcher investigates these issues and finds week evidence of flu shot efficacy. The potentially server consequences of flu shot, particularly the risk associate with pandemic disease are well-documented. The adults aged 65 or older is hard to defend the flu virus. Younger healthy adults may be at lower risk for the complications of flu. However the shot has a significant side effects on them as well.