There is no evidence to suggest that SARS (severe acute respiratory syndrome) is an airborne virus, the World Health Organization (WHO) said Monday in a report.
The report, summarizing international research on SARS, concluded that at all outbreak sites, the main route of transmission was direct contact, via the eyes, nose and mouth, with infectious respiratory droplets, the WHO regional office for the Western Pacific said in a statement.
"The finding that each patient infected on average three others is consistent with a disease spread by direct contact with virus-laden droplets rather than with airborne particles," the WHO said, noting that in airborne diseases such as influenza or measles, one person can infect an entire room by coughing.
The report, which found health workers at special risk of SARS and children rarely affected, said health workers accounted for 21percent of all cases. In some cases, transmission occurred even though they were wearing masks, eye protection, gowns and gloves.
The report said children were rarely affected, with only two reported cases of transmission from children to adults and no reports of transmission from children to other children. No evidence has been found to show SARS transmission in schools, or in infants whose mothers were infected during pregnancy.
On the other hand, research found no evidence that patients transmit the infection 10 days after fever has subsided.
The risk of a person transmitting the disease is greatest at around day 10 of the illness, when a maximum virus excretion from the respiratory tract occurs, then declines, the report said.
Research also showed that five international flights were associated with the transmission of the disease, but found no evidence of transmission on flights after the March 27 travel advisory in which the WHO recommended exit screening and other measures.
The report was released at the start of four consecutive SARS meetings being hosted in Geneva by the WHO starting Monday through Nov. 1, which will address priorities for scientific research, laboratory issues, clinical treatment protocols, and prospects forvaccine development.
More than 8,000 SARS cases and over 800 deaths in nearly 30 countries were reported between February and July, when the disease was brought under control. Over 95 percent of these cases occurred in the Western Pacific Region.
(Xinhua News Agency October 21, 2003)
