Safety of MF-59 adjuvanted vaccine for pandemic influenza: results of the vaccination campaign in an Italian health district.

Background: The occurrence of pandemic H1N1 influenza in 2009 led health authorities to promptly start massive vaccination campaigns. Due to the need of shortening time for development and approval, the pandemic vaccine was prepared by mock-up strategy, and limited safety data were available upon starting vaccine administration.

Aims: To determine the frequencies and clinical features of adverse events (AEs) observed in a population of subjects of an Italian health district receiving pandemic vaccination.