Latest New on SARS from the LANCET

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Research by UK epidemiologists and scientists from Hong

Kong, fast-tracked for publication on THE LANCET's website, reports

results of the first major epidemiological study about severe acute

respiratory syndrome (SARS). Authors of the study highlight how

concerted efforts to reduce the time from the onset of symptoms to

quarantining in hospital is one of the most important public-health

measures to reduce transmission and to potentially eradicate the

disease.

 

Christl Donnelly, Roy Anderson, and colleagues from Imperial College

London, UK, the University of Hong Kong, and the Department of

Health in Hong Kong, studied 1425 SARS cases from Hong Kong up to

April 28, 2003. They report how, after the initial phase of

exponential growth in SARS cases, public-health interventions have

led to confirmed SARS cases dropping below 20 per day by April 28.

Examples of such measures include the encouragement to report to

hospital rapidly after the onset of clinical symptoms, the tracing

of contacts of confirmed and suspected cases and quarantining, and

the monitoring and restriction of travel for contacts.

 

The average incubation period of SARS (the time between infection

and the onset of symptoms) was estimated to be 6.4 days; the average

time from the onset of clinical symptoms to hospital admission

varied from three to five days-with longer intervals reported

earlier in the epidemic. The case fatality rate, among those

admitted to hospital, in patients 60 years of age and older is

estimated to be far higher (43.3%, 95% confidence interval 35.2 to

52.4%) than in those below 60 (13.2%, 95% confidence interval 9.8 to

16.8%). Similar estimates were obtained using a second method: 55.0%

(95% confidence interval 45.3 to 64.7%) for those aged 60 or older

and 6.8% (95% confidence interval (95% confidence interval 4.0 to

9.6%) in those younger than 60. Furthermore, they comment that

additional infections in the community that do not lead to

hospitalisation or death would lower this fatality-rate estimate.

 

Christl Donnelly comments: " Although this study shows that the

fatality rate from SARS is higher than previously thought, we now

know that public-health interventions have been successfully

reducing the spread of the disease. "

 

Roy Anderson comments: " The epidemic has demonstrated the need for

communication of risk which will inform and warn the public, in a

way which will improve personal protection, without inducing high

levels of anxiety and fear, as an essential part of epidemic

control. A change in risk perception would potentially lead to an

increase in early reporting of symptoms as well as improvements in

hygiene and prevention of transmission. "

 

This study has been published early online at www.thelancet.com and

is available by clicking the link below:

http://www.thelancet.com/journal/vol361/iss9368/full/llan.361.9368.ea

rly_online_publication.25595.1

 

Ciao

 

Attilio