Larry Anderson, Centers for Disease Control and Prevention, Atlanta.
Clinical Spectrum of SARS Infection
Donald Low, Mt. Sinai Hospital, Toronto
Clinical Experience in Toronto
Chen Zhu, Shanghai Second Medical University, People's Republic of
China. Delivered by Dr. Scott Hammer
SARS: An Update from China
Panel 2 Discussion
The first appearance of SARS in people began last fall, when sporadic cases began to emerge in the southern Chinese province of Guangdong. But the seminal event triggering the current epidemic took place on February 21, when a doctor from Guangdong stayed on the ninth floor of Hong Kong's Metropole Hotel. Ten other people contracted his infection, taking it with them as they continued to travel. Within weeks, the illness popped up in other nations, including Vietnam, where it took the lives of healthcare workers such as Carlo Urbani, the World Health Organization doctor who first identified the outbreak.
The virus most frequently has been spread in hospital settings, indicating that community transmission is less likely, said Larry Anderson, M.D., chief of the CDC's Respiratory and Enteric Viruses Branch. "There is a likelihood that with good infection control practices, we can control the spread of SARS," he contended. Indeed, the infection has already been controlled in Canada, Singapore, Thailand, Vietnam, and the United States. "The good news is that the SARS outbreak has been controlled in some settings, but not in others. We still have a great deal to learn," he added.
For example, who is most likely to develop severe, if not fatal, SARS? Evidence to date indicates that elderly patients and those with diabetes or certain other co-existing chronic medical conditions are more likely to succumb to the illness, but more data is needed to confirm and explain these associations. Investigators also want to know more about the optimal time during the illness to collect specimens such as urine, respiratory secretions, and stool samples so they can correlate their findings with disease progression.
In Toronto, investigators are analyzing the blood of 100 healthcare workers who were exposed to SARS and 100 others who were not, to see if they can pinpoint any indicators of early SARS infection. Donald E. Low, M.D., chief microbiologist at Toronto's Mount Sinai Hospital, explained the SARS outbreak that, as of the date of the conference, had taken 23 lives and caused economic hardship for the city. Their saga began when a woman returned to Toronto after visiting Hong Kong. She developed SARS symptoms and died on March 5, but not before infecting her husband and her son. Her son in turn infected two other men in nearby hospital beds, who set off a chain of infection that included relatives, members of a church group that had been visiting the hospital emergency room, and patients at other hospitals in Toronto before all was said and done. The infection is now under control there.
"The outbreak is over. It is safe to come to Toronto," Low asserted, noting the valuable lessons learned from Toronto's SARS experience. One is that strict infection control is a must. Second, the disease is more often spread in hospitals—via droplets and contact—than via casual contact in the community. And finally, Low called SARS "a disease of tribes," whether those tribes include family members, hospital workers, or close communities such as religious groups.
Recent reports from China indicate that the outbreak there may be abating as well. Scott Hammer delivered a presentation prepared by Chen Zhu, Sc.D., vice president of the Chinese Academy of Sciences, who could not be at the meeting. According to his presentation, China has established a central command and ten task forces and is also evaluating potential treatments (including the serum of convalescent patients), building international collaborations, and establishing research centers to study the virus.
"The situation in China illustrates the awakening and the multidimensional approach that China is taking to control SARS," said Hammer. "It's not just a public health event, but a major political and economic event for China."