SARS Lessons Unlearned
Will SARS hit hard again this year or in the future? Experts go over what happened and what may be next.
Unusual Pneumonia continued...
By then, SARS had taken flight -- literally. The worldwide
epidemic began when a doctor who had been treating SARS patients flew to Hong
Kong and checked in at the Metropol Hotel. In just a few days, he infected at
least 17 other hotel guests. They carried the disease to Toronto, Vietnam, and
Donald E. Low, MD, chief microbiologist at Mt. Sinai Hospital
in Toronto, was in Hong Kong at that time. His hotel was down the street from
"I flew back the next day, and the SARS patient [who
carried the disease to Canada] was on the same plane the next day," Low
tells WebMD. "In that one day, SARS moved across the globe from Hong Kong
On March 12, 2003, the WHO issued a global SARS alert.
Eventually, SARS spread to 26 countries on five continents. More than 8,000
people fell ill. There were 774 confirmed SARS deaths -- about a 10%
What ended the SARS epidemic? Klaus StÃ¶hr, PhD, director of the
WHO's global SARS laboratory network, credits early identification and
isolation of SARS patients. It took heroic efforts from health officials in
Hong Kong and elsewhere, who refused to allow anyone with a fever to board any
form of transportation. Moreover, air travel to cities with ongoing SARS
outbreaks virtually ceased.
"Most countries did temperature screening," StÃ¶hr tells
WebMD. "In Hong Kong, every day there were 750,000 people screened at
airports, seaports, and land ports. Every day, several hundred people were
found to be feverish, and quite a number turned out to be suspected cases of
SARS. That is one measure that worked to limit the number of cases. Also
helpful was the recommendation to the public to suspend air travel to countries
where SARS cases were occurring in the community. These are two measures that
we considered successful."
As it turned out, SARS wasn't as easily spread as it first
seemed. Most cases could be traced to "superspreaders" -- a few people
who became especially ill with especially large doses of especially infectious
"People who were relatively close to the original source of
infection obtained a larger dose of SARS virus, were more severely ill, and
secreted a large amount of virus," StÃ¶hr says. "With each link in the
chain of transmission, the virus excretion rate changed. Those first in the
chain were most severely infected. But the super spreading was mostly seen in
the initial phase of the outbreak when people did not understand the measures
that needed to be taken."