Tempting fate is never wise; tempting a flu pandemic is downright foolish. Yet it is impossible for scientists to understand influenza or create vaccines without at least some risk. The question, then, is what level of risk is acceptable.
On December 20th the American authorities said they had asked the world’s leading scientific journals to withhold research on the matter. The request, to Science (an American publication) and Nature (a British one), is unusual. But so is the research in question. Two separate teams, led by Yoshihiro Kawaoka at the University of Wisconsin-Madison, and Ron Fouchier at Erasmus Medical Centre in Rotterdam, have tinkered with H5N1, otherwise known as bird flu. The resulting strains are dramatically more dangerous.
According to the World Health Organisation, bird flu has killed more than 330 people since 2003. That is a staggering 60% of the 570-odd cases recorded worldwide in that period. (The actual fatality rate may be lower since non-fatal cases of bird flu are more likely to escape detection than fatal ones.) The “Spanish flu” of 1918-20, which infected 500m people, claimed the lives of no more than one in five sufferers.