Influenza pandemics, whether mild, moderate or severe, affect a large proportion of the population and require a multisectoral response over several months or even years. For this reason, countries develop plans describing their strategies for responding to a pandemic supported by operational plans at national and subnational levels.
Seasonal influenza is a vaccine-preventable disease that each year infects approximately 10 to 30 % of Europe's population, and causes hundreds of thousands of hospitalisations across Europe. Vaccination is the most effective form of influenza prevention. Apart from vaccination and antiviral treatment the public health management includes personal protective measures.