Guide to revision of national pandemic influenza preparedness plans : lessons learned from the 2009 A(H1N1) pandemic

During the past decade, the 53 Member States of the WHO European Region, 31 of which are part of the European Union/European Economic Area, invested considerably in pandemic preparedness. This came in the wake of global threats posed by (re-)emerging diseases such as avian influenza A(H5N1) and A(H7N9), the SARS outbreak of 2003, and the outbreak of MERS (Middle East respiratory syndrome) which began in 2012. Adequate preparedness is also a national obligation under the International Health Regulations (2005) and the EU Decision on serious cross-border threats to health (No 1082/2013/EU). The first pandemic since 1968 occurred in 2009, caused by a new strain of influenza A(H1N1) of swine origin. The virus spread rapidly around the globe and caused only mild disease in the majority of cases. However, severe disease and deaths occurred in a significant number of people, mostly in the same groups that are at risk of complications due to seasonal influenza infection, but also in other risk groups and even in previously healthy individuals. It has been estimated that in the first year of the pandemic between 151 000 and 475 000 deaths worldwide were attributable to influenza. Healthcare services, particularly critical care units, were often stretched to their limits, and early recognition and treatment of severe disease could be life-saving. The 2009 pandemic tested national plans, and in the aftermath many countries and international organisations evaluated their preparedness and response activities. European countries, particularly in the western part of the Region, were generally better prepared for the 2009 pandemic than most countries. But when confronted with a milder pandemic than was expected, even the better prepared countries experienced gaps in their surveillance and healthcare systems. Their planning assumptions were not flexible enough, they faced difficult communications and logistics issues with respect to pandemic vaccines, and often failed to establish effective communication lines with front-line healthcare responders.