Influenza is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. It can cause mild to severe illness, and at times can lead to death. The best way to prevent flu is by getting a flu vaccine each year.
ECDC monitors and reports on influenza transmission and virus circulation in Europe on a weekly basis throughout the flu season, in collaboration with WHO Regional Office for Europe, in the report Flu News Europe.
The case definition and case finding algorithm have been prepared for surveillance purposes only and they will be adjusted as the current avian influenza A(H7N9) situation develops.
Influenza pandemics occur when new influenza viruses appear that transmit efficiently between humans and to which a substantial proportion of the population is susceptible