There are some things that we do know about “swine flu”. The H1N1 influenza virus is now a stage 6 pandemic; the virus is spreading from human to human and outbreaks are occurring around the world. The last World Health Organisation count reported 29,669 confirmed cases in 74 countries that led to 145 deaths. But, beyond that, we know nothing with certainty, other than that the danger it poses is real and governments must steel themselves to respond.

Thus far, the spread of the virus has been rapid but not particularly vicious. The majority of sufferers get mild feverish symptoms. While this unfamiliar pathogen has, on its own, been enough to kill some victims, more than half of the serious cases so far have been individuals who suffered from pre-existing conditions. The sample group, however, is still small, and infection and mortality rates may well rise or, indeed, fall.