• Through the air, by sneezing and coughing.

• Through direct contact of the hands, eyes and face.

Influenza viruses constantly evolve and are different from year to year. This makes immunity impossible and is also the reason why each year new influenza epidemics spread.

This illness is contagious and initial symptoms generally occur a few days after contagion. Those who have caught the virus are contagious even if they show no symptoms. A single person may transmit the virus even a few days after their symptoms have disappeared.

The onset of influenza is sudden. Symptoms appear all at once and are immediately severe. Body temperature rises rapidly.  Flu usually lasts a few days and its severe stage with high fever lasts from two to four days. Once the fever subsides the symptoms disappear within a few days. A feeling of weakness may persist for a few days after recovery.

Influenza may have serious complications: the most severe being bronchitis and pneumonia.