Here we go again. A new bird-flu virus in China, the H7N9 strain, is spreading alarm. It has infected about 130 people and killed more than 30. Every time this happens, some journalists compete to foment fear, ably assisted by cautious but worried scientists, and then tell the world to keep calm. We need a new way to talk about the risk of a flu pandemic, because the overwhelming probability is that this virus will kill people, yes, but not in vast numbers.
