David Dobbs at Slate thinks that the current swine flu could well be far less fatal than it might seem right now. His reasons:
Of the 110 million people in Mexico, 1,600 cases have been reported, with about 100 deaths—suggesting a mortality rate of 6 percent. This is almost certainly bad math, as the total case count almost certainly ignores thousands or tens of thousands of other cases that have taken milder courses like those in the United States. It's perfectly conceivable Mexico has actually had 10,000 or 100,000 cases—or even 1 million cases. If so, then the kill rate would be not 6 percent but 0.1 percent (given 10,000 cases) or 0.01 percent (given 100,000 cases). If it's 1 million cases (quite possible if this thing really spreads easily) then the mortality rate is just 1 in 10,000. Meanwhile, because the United States is on high alert—and can take special note of people with recent travel to Mexico—it is probably picking up a fairly high percentage of its cases, including milder instances that would have gone unnoticed in Mexico a few weeks ago.
Link via Tyler Cowen at Marginal Revolution.