Control of pandemic influenza is a critical issue and one on which the world has already spent billions of dollars, both in planning and during the recent response to pH1N1. There are obvious lessons to be learnt from the first pandemic of the 21st century, a pandemic which was much less severe than many plans had anticipated [53] . If we think our response to this pandemic was adequate, we may be falsely reassured. A more severe pandemic may find us wanting. A mild pandemic may find us over reacting. However, with appropriate collection and analysis of data it should be possible to identify the severity of future pandemics early and to make a measured response [54] . The World Health Organization, governments and other agencies around the world are currently involved in reviews of the management of the pandemic [55] . It is vital that these reviews, while not diminishing the commitment and hard work of those who implemented the response plans in 2009, carefully assess the evidence base for those plans.