Down Under hospitals are well equipped. Yet many had to struggle to keep up with severely ill swine flu patients, who have to be isolated from other patients to prevent spread of the pandemic flu.
From June through August -- winter in the Southern Hemisphere -- Australia and New Zealand ICUs admitted 15 times more patients with flu-like symptoms than in recent years.
"Our data indicate that the greatest effect on ICU resources in a given region occurs approximately four to six weeks after the first confirmed winter ICU admission, and that the extra workload lasts several weeks," report University of Western Australia researcher Steven A.R. Webb, PhD, MPH, and colleagues.
Among ICU patients with swine flu the death rate was 16%. That's the same death rate as Australian hospitals see in ICU patients with seasonal flu. But with seasonal flu, most patients with severe disease are elderly. Most patients with severe H1N1 swine flu were infants under age 12 months or adults 25 to 64.
In Australia and New Zealand, swine flu behaves very much as it does in the U.S. and elsewhere.About 30% of those with severe disease have no underlying condition.
But the majority of severe cases are among people with underlying conditions. In Australia and New Zealand, a disproportionate number of patients were pregnant, had chronic lung disease, or were morbidly obese. Indigenous populations were also disproportionately likely to be admitted to the ICU with swine flu.
Webb and colleagues report their findings in an early-release issue of The New England Journal of Medicine. Also appearing in this issue is a paper by CDC researcher Seema Jain, MD, and colleagues reporting on patients hospitalized with H1N1 swine flu from April through June 2009.
The U.S. data from last spring closely match the Down Under data from later in the year. Nearly 30% of patients hospitalized with H1N1 swine flu had no underlying condition. But most did. Those conditions have remained the same since last spring including: asthma, diabetes, heart disease, chronic obstructive pulmonary disease, neurologic disease, and pregnancy.
About one in four U.S. patients hospitalized with H1N1 swine flu were admitted to the ICU. Overall, 7% of hospitalized patients died.