Pandemics challenge the law and often highlight its strengths or expose its limits. The novel strain of influenza A (H1N1) virus that emerged in the spring of 2009 and rapidly spread around the globe was no exception. The H1N1 pandemic prompted the first significant application of a number of international legal and policy mechanisms that have been developed in the last decade to respond to this kind of event. Furthermore, it presented a considerable test for public health systems at all levels, from global to local.
Although initial predictions forecasting high morbidity and mortality from this virus overestimated its eventual impact, the human toll of the pandemic was nevertheless significant. The World Health Organization (WHO) reported approximately 1.5 million people were infected worldwide in 214 countries, resulting in over 25,000 confirmed deaths, but the actual health impact of the outbreak was certainly much higher.