Hamburg  - A seasonal influenza infection can be recognized by a classic progression through a series of symptoms typically starting with a high fever, pain in the limbs, headache and a feeling of general malaise and exhaustion.

It then progresses to the stage that includes nasal congestion, bronchitis or both and the elimination of the accompanying mucus. In addition the illness can put a strain on the cardiovascular system.

The Bavarian society for immunology and tropical disease said the seasonal flu is triggered by influenza virus A or B. People who catch the bug are badly affected for a minimum of three weeks. It can take several months before the patient's health is completely restored. Other viruses are to blame for the more common cold, which, by contrast, usually lasts about eight days and goes away much more spontaneously.

In conjunction with influenza, the patient can also suffer heart rhythm dysfunction or inflammation of the heart muscle or lungs. Other organs, including the brain, can also be affected. Elderly and chronically ill people are therefore particularly at risk of influenza having serious symptoms and even taking a fatal course.

Immunisation is an effective protection. September to November is the sensible period to receive the shot. The earlier people get it, the better their protection against the flu virus. Aside from that, getting the seasonal flu shot early leaves a sufficient gap between receiving it and receiving another inoculation for the swine flu, also called H1N1 or new influenza.

Both the Bavarian society for immunology and tropical disease and Germany's Robert Koch Institute are cautious in answering the question about whether people should be immunised against seasonal flu and the H1N1 flu at the same time. They point out that if the two immunisations are given together it could not be clearly determined which of the two might be the cause of an undesirable side effect. (dsa)