If this mutates into a more virulent flu, we're in trouble - because we just don't have enough ventilators to treat a major pandemic:

A new government study shows that one quarter of Americans who were sick enough to be hospitalized with swine flu last spring wound up needing intensive care, and 7% of them died.

Health experts say that is a little higher than with ordinary seasonal flu. They say the biggest difference is that nearly half of those hospitalized with the new swine flu have been children and teens. Flu usually strikes hardest in the elderly.

The U.S. Centers for Disease Control and Prevention did the study, with local and state health departments. Results were published online Thursday by the New England Journal of Medicine.

Researchers identified 272 patients hospitalized for at least a day from April through mid-June, when the novel virus caused its first wave of cases. That's about one-fourth of the total hospitalizations for swine flu reported during that time, but researchers only studied lab-confirmed cases and patients who agreed to be part of the study.

Three-fourths of these patients had other health problems, such as diabetes — typical of seasonal flu, too. However, only 5% were 65 and older; ordinary seasonal flu usually hits hardest in the elderly.

We're already seeing problems in other countries:

Oct. 9 (Bloomberg) -- Swine flu drove a 15-fold increase in intensive care admissions for viral lung inflammation in Australia and New Zealand, especially among pregnant women, the obese and people with chronic lung disease, a study found.

During the peak of severe illness, patients with the new H1N1 influenza strain filled 8.9 percent to 19 percent of all intensive-care hospital beds in each state of Australia and New Zealand, according to the study published yesterday in the New England Journal of Medicine. Almost 65 percent of intensive-care H1N1 patients required mechanical ventilation.

The Southern Hemisphere’s winter flu season, studied from June 1 to Aug. 31, may give health officials in the Northern Hemisphere an indication of what to expect in coming months, the researchers said yesterday. The pandemic filled all available beds in some units and prompted doctors to postpone nonessential surgery, New Zealand’s health ministry said in July.