In his Wall Street Journal column “Mind and Matter,” Matt Ridley writes that the new H7N9 avian flu strain “is spreading alarm” and “has infected about 130 people and killed more than 30.” He continues, “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.”

He briefly summarizes the histories of different flu strains and writes, “In casual-contact diseases, there is a general tendency for virulence to decline,” not become more lethal, because a virus’s job is to infect as many people as possible, which is easier when people live longer and have more contact with others. “Ironically, the most worrying sign for a bird-flu pandemic would be if the virulence dropped significantly — then it could spread. There are signs this might be happening in Egypt” with H5N1, he states, concluding, “There’s no mystery as to why we talk up the risk every time: All the incentives point that way. Who among the headline-seeking journalists, reader-seeking editors, fund-seeking scientists, contract-seeking vaccine makers or rear-end-covering politicians has even a modest incentive to say: ‘It may not be as bad as all that’?” (5/10).