Finally…The World Health Organization said Tuesday that it was moving closer to declaring swine flu a worldwide pandemic.
The disease has reached 64 countries, and there have been dozens or hundreds of cases in several nations outside North America, including Britain, Spain, Japan, Chile and Australia.
The Southern Hemisphere countries are now of chief interest because their winter flu season is just beginning and another strain of the H1N1 virus, widespread last winter, was resistant to the antiviral drug Tamiflu.
To raise the flu alert to its highest level, Level 6, the W.H.O. would need to find evidence of widespread “community transmission” — meaning beyond travelers, schools and immediate contacts — on two continents. Dr. Keiji Fukuda, the agency’s chief of flu, said that finding had not been made.
The agency is debating new rules for assessing global disease outbreaks. If it declares a Level 6 pandemic, Dr. Fukuda said, it may add a caveat indicating that the virus is not very lethal. The flu has been blamed for only 117 deaths.
Still, measuring severity can be tricky because the same flu virus may theoretically kill far more people in a poor country with widespread malnutrition and AIDS than it does in a wealthy, well-fed nation.
No cases have been reported anywhere in Africa. Historically, there has been little flu surveillance on the continent, which has many more serious diseases to track, though South Africa has a laboratory that regularly reports cases to the W.H.O.
In the United States, the flu finally reached all 50 states this week. It has been blamed in at least 19 deaths.
But it has spread very unevenly across the country. For example, flu has closed many New York City schools, but the virology lab at the University of California, San Francisco, has not found a positive flu sample in the Bay Area in weeks, even though the country’s first identified case was in Southern California in April.
Seasonal flu shots appear to offer no protection against swine flu. Scientists from the National Institute for Infectious Diseases in Tokyo looked at 43 laboratory-confirmed cases from Kobe and reported this week that those who had been vaccinated did not seem to get swine flu less often than other patients. The observations confirmed what American scientists had found in blood tests in the lab.