Swine Flu H1N1 Pandemic

New flu hit estimated 10 percent of New Yorkers

The new H1N1 Swine Flu is estimated to have infected about 800,000 people in New York City in the spring, a top U.S. health official said on Sunday, citing a study due to be released later this week. Dr. Thomas Frieden, who heads the U.S. Centers for Disease Control and Prevention, said surveys suggested the virus was widely spread around the city. Frieden was New York City's health commissioner before taking the top CDC job in June.

"In New York City where we had a lot of H1N1 this last spring the estimate is about 800,000 people, about 10 percent of New York City residents, got infected with the flu," Frieden said in an interview with C-SPAN television aired on Sunday. "That's a lot of people."

WHO Warns of Severe Form of H1N1 Virus

Doctors are reporting a severe form of H1N1 that goes straight to the lungs, causing severe illness in otherwise healthy young people and requiring expensive hospital treatment, the World Health Organization said Friday. Some countries are reporting that as many as 15 percent of patients hospitalized with the new H1N1 pandemic virus need intensive care, further straining already overburdened healthcare systems, WHO said in an update on the pandemic.

"During the winter season in the southern hemisphere, several countries have viewed the need for intensive care as the greatest burden on health services. Preparedness measures need to anticipate this increased demand on intensive care units, which could be overwhelmed by a sudden surge in the number of severe cases."

Earlier, WHO reported that H1N1 had reached epidemic levels in Japan, signaling an early start to what may be a long influenza season this year, and that it was also worsening in tropical regions.

WHO says swine flu down in Southern Hemisphere

The World Health Organization said Friday that swine flu infections are declining in the Southern Hemisphere as its seasonal flu period comes to an end and the pandemic shifts back north. Countries in the Northern Hemisphere that have already had one wave of swine flu should prepare for a second wave, which may be worse, the agency said.

"The H1N1 pandemic virus has rapidly established itself and is now the dominant influenza strain in most parts of the world. The pandemic will persist in the coming months as the virus continues to move through susceptible populations."

Clinicians from around the world are reporting a very severe form of the disease in young and otherwise healthy people. "In these patients, the virus directly infects the lung, causing severe respiratory failure," WHO said. Therefore, countries should anticipate a growing demand for treatment in intensive care units as they prepare for a second wave of the pandemic.

• World Health Organization, Pandemic (H1N1) 2009 website.
• U.S. Center for Disease Control and Prevention, 2009 H1N1 (Swine Flu) website.
• Medline Plus (Encyclopedia), H1N1 Flu (Swine Flu) website.