Vaccine-preventable influenza disease burden from clinical trials of Vaxigrip - an inactivated split virion influenza vaccine - supports wider vaccine use.

Trivalent inactivated split influenza virus vaccine has been used for more than 35 years, and is currently licensed in over 100 countries. To determine vaccine-preventable influenza burden in different populations and geographic regions, we reviewed studies of vaccine effectiveness against non-specific outcomes such as upper respiratory infection, hospitalization, and death in addition to confirmed microbiologically confirmed influenza. The vaccine-preventable disease incidence was high in most studies, regardless of the outcome or population evaluated. This indicates that routine influenza vaccination can improve overall population health under a broad range of circumstances.