How does a flu shot work with the immune system?

A flu shot works by introducing inactivated or weakened strains of the influenza virus into the body, prompting the immune system to recognize these antigens as foreign invaders. This triggers an immune response, leading to the production of antibodies specific to the virus. If the vaccinated individual later encounters the live virus, their immune system can quickly recognize and combat it, reducing the severity of illness or preventing infection altogether. Essentially, the flu shot prepares the immune system to respond more effectively to future infections.