The World Health Organization reports it has received nearly 6,500 officially confirmed cases of swine influenza A-H1N1 - including 65 deaths - from 33 countries. While this is serious, WHO says the disease has not yet become a pandemic.
The World Health Organization says it needs to see clear evidence of sustained community transmission of the swine flu virus from person-to-person in at least two regions of the world before it raises its alert to the phase six pandemic level.
And that, says WHO Assistant Director-General, Keiji Fukuda, has not yet happened in any region outside North America. He says all of the infections, which have occurred in other parts of the world have stemmed from people who had been traveling in North America.
"Currently, many of the people who have not traveled, we know have been in contact with the travelers returned," said Fukuda. "However, if we begin to see numbers of people who are getting infected who have not any contact with such persons, then this really becomes much stronger evidence that we are seeing community to community spread."
Fukuda notes a pandemic has nothing to do with the severity of the disease, but rather with its geographic spread. He says it is difficult to know how the disease will evolve. So far, he says it has been relatively mild.
So, he counsels people not to over-worry. But, he warns against complacency. He says people must remain vigilant. He says it is very important to monitor and closely follow the course of the disease.
"This is an event which is serious," said Fukuda. "This is something, which requires close monitoring. But most of the cases at this time, continue to be mild cases where people recover without needing hospitalizations. Although there are some people that do get fatalities and serious illnesses."
There were three influenza pandemics in the 20th century. The most serious occurred in 1918 when upwards of 50 million people are believed to have died.
Those pandemics disproportionately killed younger people, a phenomenon, which is different from seasonal flu.
Fukuda notes most deaths from seasonal flu are among people older than 65 or those who have chronic medical conditions. He says in the current outbreak, most deaths are occurring among young, healthy people. In this sense, he says the pattern appears to be similar to that, which occurred during the three 20th century pandemics.