Hemos llegado a un nivel de alerta que no hubo cuando la gripe aviar:

"Because of the situation, the World Health Organization planned to consider raising the world pandemic flu alert to 4 from 3. Such a high level of alert — meaning that sustained human-to-human transmission of a new virus has been detected — has not been reached in recent years, even with the H5N1 avian flu circulating in Asia and Egypt, and would “really raise the hackles of everyone around the world,” said Dr. Robert G. Webster, a flu virus expert at St. Jude Children’s Research Hospital in Memphis."

http://www.nytimes.com/2009/04/25/world/americas/25mexico.html?bl&ex=1240891200&en=ce91d53e13153eed&ei=5087