Seasonal influenza vaccines
Influenza is a vaccine preventable disease and influenza vaccines have been available for use in Europe since the 1960s.
A number of variants of the influenza viruses co-circulate each year. Immunity to the infecting influenza virus type develops following a natural influenza infection. However, there is little cross-immunity between influenza types/subtypes or lineages. This is why several influenza strains must be included into combination vaccines.
Due to the rapid virus evolution influenza viruses go through the combination vaccines must be updated yearly.
Currently most influenza vaccines used in the European Union/European Economic Area (EU/EEA) contain three different influenza strains (trivalent): two influenza A (H1N1 and H3N2 subtypes) and one influenza B (Victoria or Yamagata lineages).
Starting from the influenza season 2014-15 new quadrivalent combination vaccines containing four different influenza strains gradually are becoming available. These vaccines contain two influenza A (H1N1 and H3N2 subtypes) and two influenza B (Victoria and Yamagata lineages) strains.
Seasonal influenza vaccination strategies
The immunity that is elicited by influenza vaccines is not as long lived as the immunity following natural influenza infection. This is especially so for individuals in the so-called risk groups, hence people have to be vaccinated annually.
Risk groups for severe influenza
The influenza risk groups include people who are more likely than others to develop severe disease, should they be infected.
Types of seasonal influenza vaccine
Injected trivalent inactivated influenza vaccines are most commonly used throughout the world. Influenza antigen preparation varies between manufacturers.
Yearly updates of influenza vaccines
An update of seasonal influenza vaccines is needed yearly, since influenza viruses constantly evolve.
Infographic: Why do I need a flu vaccine every year?
Every year flu is different, so every year you need an updated vaccine. Usually, a flu vaccination reduces the risk by 60%. In a bad year, the seasonal flu vaccine reduces the risk of flu illness by only 20% to 30% in the overall population.
Immunity following influenza disease and administration of influenza vaccines
For infants the first encounter with influenza viruses commonly occurs in their first or second winter season. Subsequently, each individual acquires a number of influenza infections throughout life.
Timing of influenza vaccination
It takes 10 to 14 days following vaccination, before an immune response and protection develops. Therefore, most countries start immunisation in the early autumn.
Vaccine schedules for seasonal influenza in all countries of the European Union
The Vaccination Schedule is an interactive platform of vaccination schedules for individual European countries and specific age groups.
Influenza vaccination coverage
The Council has set clear vaccination coverage targets for the elderly and risk groups and the EU Member States have agreed to have strong influenza immunisation programmes for the elderly and risk groups.
Influenza vaccine effectiveness
To establish how well influenza vaccines work each season, influenza vaccine effectiveness is measured in observational studies.
More about immunisation
Immunisation and vaccines
Vaccines represent one of the most effective and cost-saving public health intervention.Read more
Vaccine hesitancy refers to delay in acceptance or refusal of vaccines despite availability of vaccination services. Vaccine hesitancy is complex and context specific varying across time, place and vaccines. It includes factors such as complacency, convenience and confidence.Read more