It is almost three years since we faced the hysteria of an avian flu epidemic, when governments bought billions of dollars of Tamiflu - the same anti-viral now being promoted to combat a supposed swine flu pandemic. The shelf life of Tamiflu also happens to be three years.
The World Health Organization has, at the time of writing, increased its threat level to five, which means governments can activate their pandemic plans - and start handing out Tamiflu drugs.
This is extremely convenient for governments that would have very soon have to dispose of billions of dollars of Tamiflu stock, which they bought to counter avian flu, or H5N1. The US government ordered 20 million doses, costing $2bn, in October, 2005, and around that time the UK government ordered 14.6 million doses. Tamiflu's manufacturer, Roche, has confirmed that the shelf life of its anti-viral is three years.
England's chief medical officer Sir Liam Donaldson has said that the UK is "well prepared" to counter swine flu - but only because it was well prepared to counter an avian flu pandemic that never happened.
The other worry is when, or if, medicine comes up with a specific anti-viral for swine flu. The last time they did - when we had the last swine flu scare in 1976 - health officials rushed through a vaccination programme that resulted in 1 out of 100,000 vaccinated Americans developing Guillain-Barre paralysis. The US government paid out $93 million in compensation.
Those of us who quaked in fear from the expected SARS epidemic and shook from the anticipated avian flu pandemic may feel they've been here before. Despite the dire warnings, at the time of writing just 2,600 cases of swine flu have been confirmed or suspected around the world , and there have been 160 deaths, and not all of these may turn out to be caused by swine flu. More people die on UK roads every month.
Meanwhile, while we're blaming the Mexicans for starting the anticipated global pandemic of swine flu, who are the Mexicans blaming?
Several of their newspapers are pointing the finger at local plants of Smithfield Foods, the world's largest pork packer and hog producer. Mexican journalists report on concerns from locals in Perote, Santa Cruz, Mexico - where the outbreak was believed to have started - that the pig breeding farm polluted the atmosphere and local water supplies.
A municipal health official seems to support the locals' concerns, and says the outbreak may have been started by flies that reproduced in the pig waste.