Should you be worried about avian flu?

Richard Posner says yes:

The world in general and the United States in particular are unprepared for a flu pandemic. Although the current strain of avian flu was discovered eight years ago, vaccine development and production are just beginning, along with stockpiling of Tamiflu. Apparently there is at present only enough vaccine for 1 percent of the U.S. population. Roche has only a limited capacity for producing Tamiflu and, as mentioned, is reluctant to license other pharmaceutical firms to produce the vaccine. The President recently announced a $7.1 billion program for improving the nation's defenses against flu pandemics, but it will take years for the program to yield substantial protection.

So we are seeing basically a repetition of the planning failures that resulted in the Hurricane Katrina debacle. The history of flu pandemics should have indicated the necessity for measures to assure an adequate response to any new pandemic, but until an unprecedented number of birds had been infected and human beings were dying from the disease, very little was done.

The causes are the familiar ones. People, including policymakers, have grave difficulty taking measures to respond to risks of small or unknown probability. This is partly because there are so many such risks that it is difficult to assess them all, and the lack of solid probability estimates makes prioritizing the risks inescapably arbitrary, and it is partly because politicians have truncated horizons that lead them to focus on immediate threats to the neglect of more remote ones that may be more serious. ("Remote" in the sense that, if the annual probability of some untoward event is low, the event, though it could occur at any time, would be unlikely to occur before most current senior officials leave office.) But by the time a threat becomes immediate, it may be too late to take effective response measures.

There is also a psychological or cognitive impediment--an "imagination cost"--to thinking seriously about risks with which there is little recent experience. Wishful thinking plays a role too. There is the inverse Chicken Little problem: the illogical reaction that because the swine-flu pandemic never materialized, no flu pandemic will ever materialize. Another example of wishful thinking is the argument that most people afflicted by the Spanish flu in the 1918-1919 pandemic died not of flu, but of bacterial diseases such as pneumonia that the flu made them more vulnerable to. But, first, is is far from clear that "most" died of such diseases, and, second, the current strain of avian flu appears to be more lethal than the Spanish flu. Only about 1 percent of Spanish flu victims died, whereas 50 percent of known human victims of the current avian flu have died. That percentage is probably an overestimate because many of the milder cases may not have been reported or may have been misdiagnosed; but it is unlikely that the true fatality rate is only one-fiftieth of the current reported rate. It is estimated that even a "medium-level" flu pandemic could cause up to 200,000 U.S. deaths and a purely economic impact (that is, ignoring the nonpecuniary cost of death and illness) of more than $150 billion.

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