Once upon a time, a village asked its nerds to warn it when wolves threatened the chickens. One day the nerds saw wolf tracks - but how many wolves were there, and how hungry? The forest was big and there was not enough time to find out before sunset, so the nerds advised the panicked villagers to buy rifles.
But before the rifles were even loaded, one small and skinny wolf slunk out of the woods, killed two chickens and ran away. The nerds tried to explain that there were probably more wolves out there, but the angry villagers took the rifles back to the store and lynched the nerds.
This is the parable of swine flu. Governments had asked the World Health Organization to coordinate their response to flu pandemics, and when one broke in April 2009 the WHO did exactly that, triggering expensive government health measures and vaccine purchases.
Critics now allege the flu was less deadly than normal flu, meaning vast sums of public money were wasted on nothing more than a scare. Some even claim that it was a conspiracy to boost vaccine company profits.
So were the WHO and governments right to respond as they did? Or was it all an expensive overreaction, or a hoax? This week an independent inquiry by a WHO committee delivers its preliminary answers to these questions. Similar inquiries are under way in the UK, the US and elsewhere.
Here's the answer I hear from scientists: declaring a pandemic and making vaccine were overwhelmingly the right things to do given the science and technology at our disposal.