evidence: During the 2009 H1N1 pandemic, solid organ transplant (SOT) recipients in Switzerland received two doses of an AS03-adjuvanted influenza vaccine (Pandemrix). The authors compared the safety and immunogenicity of two doses of AS03-adjuvanted vaccine in more than 200 SOT recipients (heart, lung, liver, kidney, pancreas/islet of Langerhans) to one dose in healthy family controls. Adverse reactions occurred less frequently in the SOT group and SOT graft function remained unaffected.