Seasonal influenza is a highly contagious viral disease, which typically occurs as epidemics during the cold months. This respiratory infection may include symptoms like fever, cough, pains and weakness. Annual outbreaks of influenza are due to minor changes in the virus. These changes enable the virus to evade the immunity developed by humans after previous infections or in response to vaccinations. Every year, some 100 million people are affected in Europe, Japan and the USA alone.
A European Influenza Surveillance Network (EISN) led by the European Centre for Disease Prevention and Control (ECDC) aims at reducing the burden of the disease in Europe through regular exchange of information on influenza activity.
On 22 December 2009, the Council adopted a Recommendation on seasonal influenza vaccination aiming at a coverage of 75% for at risk groups by 2014-2015 winter season.
Influenza strains from animal origin
Some influenza strains can also be found in animals. Under certain circumstances, they can be communicable to humans and can cause high morbidity and mortality in human populations. Animal husbandry systems where humans live in close cohabitation with poultry and pigs are considered the most likely source of new strains, capable to cross the species barrier from animal to man, through a mutation mechanism, and may cause a pandemic.
An influenza pandemic occurs when a radical change in influenza virus takes place. There have been three pandemics in the last century. The change is so radical that affected humans have no immunity against this new virus. With increased mobility of people, as well as conditions of overcrowding, epidemics due to a newly emerging influenza virus are likely to spread quickly all around the world and are at risk to eventually become a pandemic. It is therefore important to be prepared to this eventuality.