"Flu infection" refers to being sick with the flu. It means that your body has been invaded by a virus called the flu virus, which can cause various symptoms like cough, fever, sore throat, body aches, and tiredness. When you have a
flu infection, your immune system fights against the virus to help you get better. It is important to take care of yourself, rest, and drink lots of fluids when you have a
flu infection. Full definition