Image courtesy World Health Organisation Department of Microbiology - The University of Hong Kong and the Government Virus Unit - Department of Health - Hong Kong SAR China Coronavirus from SARS isolated in FRhK-4 cells. Thin section electron micrograph

SARS is not the first 'killer virus', and will undoubtedly not be the last. History has a habit of knocking down those that ignore the lessons it teaches. In 1918 a strain of influenza hit the world like a thunderbolt. An estimated twenty five times more deadly than normal influenza, it was fatal in around 2.5% of cases and has been estimated to have killed anywhere between 20 and a 100 million people worldwide. To get that in perspective, somewhere around 28.5 million people are estimated to have been killed in the two world wars combined. Global population in 1918 was around the 1.8 billion mark, whereas now it is estimated at about 6.3 billion. The very real fear is that with a worldwide population that is over three times larger than the 1918 influenza outbreak, any virus that takes hold with anything like the same ferocity could potentially be catastrophic.

SARS currently has a death rate of about 6% of those who catch it succumbing to it; but in some areas, like Beijjing in China, the rate seems to be climbing up to 10%. There is also the problem of air travellers acting like latter day 'plague rats', and spreading the virus; and so the WHO is right to nip tragedy in the bud and stop SARS flowering out of control. In 1918 the death rate may have been much lower (2.5%), but those affected was much higher. More than 20% of the worlds population became ill. If these figures were repeated today more than 1.2 billion people would be ill; or in other words the approximate population of North America and Europe combined.