Impacts on influenza A(H1N1)pdm09 infection from cross-protection of seasonal trivalent influenza vaccines and A(H1N1)pdm09 vaccines: Systematic review and meta-analyses

► Systematic reviews of cross-protection of TIVs & A(H1N1)pdm09 vaccine effectiveness. ► TIVs provided moderate cross-protection against confirmed A(H1N1)pdm09 illness. ► A(H1N1)pdm09 vaccines were highly effective against confirmed illness.