The number of confirmed cases of the disease rose above 1,200 in Australia on Monday and the virus is no longer restricted to schools and other institutions in that country, suggesting that a community-wide spread has begun. Such a spread in a region outside North America is the primary criterion for raising the alert level to Phase 6…
…they are concerned that infections continue in North America and Europe, even though the traditional flu season has ended in the Northern Hemisphere. “The disease patterns are not what we see from seasonal influenza,” he said. That suggests that the virus has greater capability for spread than does the seasonal flu virus.
The majority of the infections have been in people younger than 60, which is also different from seasonal flu. That suggests, some experts said, that older people may have been exposed to a different swine flu virus in the past that has conferred some immunity.
About half of the people who have died from the virus were previously healthy, with no underlying medical conditions. “That is one of the observations that has given us the most concern,” he said. “We don’t know why they died and why other people recovered. We are looking for clues.”