Two new studies suggest that the virus that causes severe acute respiratory syndrome (SARS) would cause a very large global epidemic if left unchecked. But they also state that the disease is not so contagious as to be uncontrollable, provided that basic public health measures are put in place.
In the first scientific assessments of the epidemic potential of SARS and the effectiveness of control measures, two teams of researchers used mathematical models to calculate the potential spread of the disease. They report in the journal Science that measures such as early detection, isolation of patients, treatment with antiviral drugs and quarantine of exposed individuals can have a major impact on the epidemic.
"Considerable effort will be necessary to implement such measures in those settings where transmission is ongoing, but such efforts will be essential to quell local outbreaks and reduce the risk of further global dissemination," according to Marc Lipsitch of the Harvard School of Public Health, United States and colleagues.
But the findings are still less than fully comforting, say Chris Dye and Nigel Gay of the World Health Organisation in an accompanying article in Science. "The mathematical models are complex, the data are poor, and some big questions remain," they say, notably "whether we can move from local control to global eradication".
And researchers warn that although the virus appears to have been contained in most developed countries, some poor nations are still vulnerable. "Dangers still persist in populous regions of the world with a limited public health infrastructure and poor disease-reporting systems," write Steven Riley from Imperial College London, United Kingdom and colleagues.
Reference: Science, 20 June 2003
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