The flu, also known medically as influenza, is an acute infectious disease caused by viruses. It manifests itself with typical symptoms such as sudden fever, severe headache and aching limbs, dry cough, runny nose, sore throat and general malaise. In more severe cases, the flu can also be accompanied by serious complications such as pneumonia. The flu viruses are transmitted by droplet infection. This means that they can be transmitted through coughing, sneezing, but also through direct contact with infected surfaces or people. The incubation period is usually around one to four days, during which the infected person is not yet aware that they are carrying the virus and are already contagious. In contrast to a simple flu-like infection, the flu is often much more severe and prolonged. Those affected feel extremely exhausted, have no appetite and are usually confined to bed for several days. The flu can have serious health consequences, especially for older people, the chronically ill and pregnant women, as the immune system is weakened and the body is more susceptible to further complications. It is also important to wash your hands regularly and thoroughly, avoid crowds of people during the flu season and take immune-boosting measures such as a healthy diet, sufficient sleep and regular exercise.