Pandemic unadjuvanted influenza A (H1N1) vaccine in dermatomyositis and polymyositis: Immunogenicity independent of therapy and no harmful effect in disease

► Pre- and post-vaccination disease and muscle parameters were comparable. ► The vaccine was well tolerated without any severe adverse effects during follow-up. ► Seroconversion, seroprotection rate, GMTs and FI in the GMTs were comparable.