Fact sheet for the general public 
In Europe influenza occurs in regular winter epidemics, though the intensity of infection varies from year to year.

Human influenza viruses
Human influenza viruses are RNA viruses from the family Orthomyxoviridae. They are usually classified into three broad types A, B and C according to differences in the antigenic properties of their external coat.

Q&A on seasonal influenza 
What is influenza? Influenza is an infectious respiratory illness caused by infection with an influenza virus.  Not everyone who becomes infected gets sick but for those that do, common symptoms include headache, fever, cough, sore throat, aching muscles and joints and generally feeling awful.

Seasonal influenza vaccines (see Vaccines section)
Human influenza viruses are well adapted to their hosts. That is they infect humans easily and transmit easily from one human to another, usually without killing their hosts. Immunity comes either from experiencing infection or from vaccination.

Q&A on seasonal influenza vaccines (See Vaccines section)
Should I be vaccinated against influenza? For people in a Risk Group the most important way of preventing the serious complications of influenza is the annual flu vaccine early in the autumn, and taking general precautions.

Q&A on antivirals and seasonal Influenza (see Antivirals section)
What are the uses of antivirals against seasonal influenza? The policy and practice on the use of antivirals varies between European countries. In some countries, using evidence-based policies, antivirals are only recommended for adults who are at increased risk of the complications of flu.