Long-term influenza vaccination, if you are not allergic to the vaccine and do not experience any adverse reactions, then there are generally no adverse consequences, usually the influenza vaccine on the human body to protect the time of about 1 year. Long-term influenza vaccination generally does not produce adverse effects, after the influenza vaccine may appear fever, headache, redness and swelling at the site of vaccination and other adverse reactions, these adverse reactions can usually subside within 2~3 days, without too much worry, but need to pay attention to, to the influenza vaccine in any component of the allergy of the population should not be vaccinated with influenza vaccine. In addition, patients with fever, patients with uncontrolled neuropsychiatric disorders, and patients with acute illnesses or acute exacerbations of chronic diseases should not receive the vaccine. The flu vaccine protects the human body for about 1 year, and after 1 year, a new flu vaccination is needed to continue the protective effect. If you need to be vaccinated against influenza, please consult your local CDC or vaccination department before getting vaccinated.