The death rate from SARS could be higher than original estimates, according to a new international study.
The percentage of people dying from the disease is already running higher than the infamous Spanish flu that killed more than 20 million people worldwide in 1918.
Medical staff are becoming increasingly alarmed as more is learned about the SARS virus. Aside from the high death toll, research published earlier this week showed that it could survive for periods outside a host, and studies of its genetic blueprint showed it was a unique type of virus.
The British medical journal, the Lancet, yesterday published a study by Chinese and UK research teams of SARS hospital admissions in Hong Kong. It suggests that the estimated fatality rate for Hong Kong SARS could be as high as 20 per cent or one death for every five cases of the disease.
The death rate from a typical flu is about 0.1 per cent, and the Spanish flu killed between 2.5 and 5 per cent of those who caught it. The current worldwide SARS death rate based on figures published yesterday by the World Health Organisation stood at 7.1 per cent.
Figures from the Lancet study looked bleak, but there were severe limits to what could be inferred from the Hong Kong study, according to Prof Greg Atkins, head of virus studies at Trinity College's Moyle Institute. "Their estimate is about 20 per cent, but they think their own estimate is too high," he said yesterday.
The death toll was based on those admitted to hospital for the disease, with a particularly high death rate found among the elderly.
Many younger people may have contracted SARS without having attended hospital, something that would reduce the death rate. It also only looked at Hong Kong cases and not other regions, Prof Atkins said.
"The distribution of cases in Hong Kong is very peculiar," he said.
It was clustered around the harbour areas in particular. "It seems to suggest it is an area with poor hygiene or lots of people."
While the 1918 flu killed fewer than one in 20 people who contracted it, the very high number of deaths occurred because huge numbers of people became infected. "Although it killed a lot of people, a lot of people got it," Prof Atkins said.
Two studies of the SARS viral genome published last week showed it to be a unique form of the coronavirus group to which it belongs.
"It is not related to any known human strain, but it is not related to animal strains either. Where it came from is a bit of a mystery," he said.
The research showing it could survive for a time outside the body was not a surprise, he added. The SARS virus can survive many common disinfecting agents but is readily killed with bleaches and detergents, he said.