Anat Gesser-Edelsburg, Emilio Mordini, James J. James, Donato Greco and Manfred S. Green.

When the H1N1 influenza pandemic broke out in 2009, health organizations (World Health Organization [WHO] and Centers for Disease Control and Prevention [CDC]) did not operate in a vacuum. Health regulations and insights from previous influenza epidemics guided the risk management of the H1N1 influenza outbreak and the strategies used to communicate with the public. Most countries, following the 2002 and 2005 WHO guidelines, prepared national pandemic plans, which in many cases were updated with the second WHO guidelines. Those plans also were analyzed in the scientific literature. Thereafter, all of the procedures followed by the CDC and WHO were documented in final reports, which summarizes their activity during the 2009 outbreak.