SARS death rate up to 43%

SARS (Severe Acute Respiratory Syndrome) is a more dangerous disease than previously thought, epidemiologists conclude in a paper published today. But this is not attributed to the mutation rate of the causative agent — it's a consequence of simple epidemiological arithmetic and a misunderstanding of the low mortality figures published by the World Health Organization (WHO).

The death rate from SARS in Hong Kong is 43% in those over 60 years old (35–52%, at 95% confidence), and 13% in the under 60s (10–17%, at 95% confidence). These are the key results of the first thorough epidemiological study of the SARS outbreak, published today (May 7, 2003) in The Lancet online, by Roy Anderson of Imperial College London, working with colleagues in London and Hong Kong.

Mark Salter, WHO's coordinator for the clinical management of SARS, told The Scientist today that he thought "the mortality in the older age group seemed ...