Pandemic H1N1 influenza caused a 15-fold increase in admissions to intensive care units for lung problems is Australia and New Zealand during the winter flu season, researchers reported today in the New England Journal of Medicine, offering a foretaste of what might be expected in the United States this winter. In a separate study in the same journal, U.S. researchers reported that a quarter of Americans who were hospitalized with influenza symptoms last spring ended up in the intensive care ward and that 7% of them died. Both groups of researchers concluded that swine flu was slightly more dangerous than seasonal flu. The biggest difference is that seasonal flu is most serious in the elderly, while about half of those hospitalized with swine flu were children and teenagers.
The seasonal flu season, which officially began last weekend in the United States, is now winding down in the Southern Hemisphere, and insights gained there may give some clue about what will happen here if the virus does not mutate. The Australian and New Zealand team studied all intensive care units in the two countries during the winter and found that 722 patients were admitted with laboratory-confirmed swine flu. Of those, 669 were under the age of 65 and 66 were pregnant women. The admissions filled all available beds in some units and forced doctors to postpone some elective surgeries. More than 16% of patients admitted to the units died, a total of 103. As has previously been observed, those at the greatest risk for severe complications were infants under the age of 1, adults ages 26 to 64, pregnant women, the obese and indigenous people.
The U.S. team, headquartered at the Centers for Disease Control and Prevention, studied 272 patients admitted to hospitals with laboratory-confirmed swine flu from April through mid-June. They accounted for about a quarter of all flu-related hospital admissions during the period. Forty-five of them were under the age of 5, and only 5% were older than 65 -- a sharp contrast to the normal populaton distribution with seasonal flu. Among the 272 patients who were the first hospitalized in each state, nearly three-quarters had an underlying medical condition, such as asthma, diabetes, heart disease and neurological problems. Two hundred of the patients received antiviral drugs, which seemed to help, even though they were typically administered beginning two days after the onset of illness.
So, if you are thinking about organizing a swine flu party to catch the virus before it can potentially mutate into a form that is more lethal, you might want to reconsider. The current form of the virus is already bad enough.
-- Thomas H. Maugh II