"All countries should immediately now activate their pandemic preparedness plans. Countries should remain on high alert for unusual outbreaks of influenza-like illness and severe pneumonia."

"The international community should treat this as a window of opportunity to ramp up preparedness and response."

"After all it really is all of humanity that is under threat during a pandemic."

"For the first time in history we can track the evolution of a pandemic in real time. Influenza viruses are notorious for their rapid mutation and unpredictable behaviour."

"This change to a higher phase of alert is a signal to governments, to ministries of health and other ministries, to the pharmaceutical industry and the business community that certain actions now should be undertaken with increased urgency and at an accelerated pace."

"Based on assessment of all available information and following several expert consultations, I have decided to raise the current level of influenza pandemic alert from phase 4 to phase 5."

"Influenza pandemics must be taken seriously, precisely because of their capacity to spread rapidly to every country in the world."