 Three surveillance systems in Legoria region, northern Italy, were used to estimate the burden of influenza and describe genetic evolutionary pattern and antigenic variability of type B viral strains, showing that type B virus predominated or played a relevant role in 50% of evaluated influenza seasons and frequent co-circulation of both lineages with heterogeneous circulation of different influenza B strains, determining partial or complete mismatch in at least six influenza seasons. The integration of different surveillance systems helps estimate the poorly evaluated burden of type B influenza virus and find variants to include in vaccine formulation. This article was authored by Cecilia Trocci, Cristiano Alicino, Andrea Orsi, and others.