As the spread of the SARS epidemic in Canada lurks threateningly close to the United States border, researchers at the Human Vaccine Institute are pursuing the development of a SARS vaccine and Duke public health officials are trying to make sure that all the necessary safety precautions are in place.
SARS is a new form of the corona virus, only 30 percent identical to any previously known corona viruses. With more than 8,000 cases and an approximately nine percent mortality rate, the SARS epidemic has "enormous societal, economic [and health] implications," said Dr. Larry Liao, associate professor of medicine at the HVI.
Experts are currently unable to forecast how long the disease will remain a dangerous threat, although Dr. Julie Gerberding, director of the Centers for Disease Control and Prevention and administrator of the Agency for Toxic Substances and Disease Registry, said in a conference call with University public health officials last week that she is "cautiously optimistic" that the outbreak of SARS is being brought under control. Others, however, are not persuaded.
"SARS has the potential to be a serious pandemic," said Dr. Bill Christmas, director of Student Health and clinical professor of community and family medicine. "SARS is a moving target and conditions are expected to change."
Director of the HVI Dr. Barton Haynes said he does not believe the epidemic will go away because animals will still be able to host the virus. "It'll come back," he said.
In a recent study by the World Health Organization, Chinese cats, badgers and dogs were discovered with SARS, though the WHO said in a press release that "it was impossible to tell from the study whether any of the animals spread the virus to humans or whether they caught the virus from people."
Research geared toward the development of a vaccine for SARS, despite the unclear long-term implications of the virus, is "moving quickly," Haynes said. It took a couple weeks to culture the virus and another six days to sequence the 28,000+ nucleotides, which were immediately released on the Internet so that researchers around the world could have access to the information.
"When the U.S., Canada and the Western world started to get involved in the research for SARS, we got the full picture of the virus in just about two weeks," Liao said. "I could not appreciate more how high the quality of work for the SARS virus has been."
The impressive global collaboration on SARS research is due in large part to the United States' campaign to combat newly emerging infectious diseases and antibioterrorism efforts since the Sept. 11 attacks. As an integral component of the Southeast Regional Center of Excellence for Biodefense, the HVI has made a significant effort to search for new vaccines for anthrax, smallpox and SARS.
"We have accumulated a number of years of experience in vaccine development, and because of this, I think we can contribute to the SARS research," Liao said.
In collaboration with investigators from the National Institutes of Health and working groups from the University of North Carolina at Chapel Hill, University of Alabama at Birmingham, Emory University, Vanderbilt University and University of Florida, Duke is in the process of developing a subunit vaccine, in which a surface antigen such as a protein, will produce an antibody immune response to neutralize the effects of the virus.
Because SARS patients in Hong Kong and China treated with the serum of recovered patients recovered, the subunit vaccine "holds promise," Liao said.
The Spike protein has been identified as the site, or epitope in the virus as having the neutralizing characteristics. Researchers are currently in the stage of optimizing the expression of the Spike protein's genes, which will take another four to six weeks before all 1,500 amino acids are optimized. Then the vaccine with be tested in animals to see if it induces an antibody neutralizing response.
In the meantime, while there have been no 'probable cases of SARS' in the U.S., eight suspected cases of SARS in North Carolina-two as near as Raleigh-were investigated "back in the early days of the epidemic," according to Dr. George Jackson, director of Employee Occupational Health.
"SARS is certainly a risk for the health care setting, particularly in the case that a SARS patient goes [undiagnosed]," said Dr. John Engemann, a medical fellow at Duke. "If you're caring for patients with suspected SARS, health care providers should have proper protection."
Such suspicions of SARS as well as the fact that 75 percent of the virus's transmission has occurred through health care workers in the health care setting, stress the importance of the Medical Center's goal to "make sure that the necessary mechanisms are in place to deal with a suspected case of SARS," said Sharon Henricksen, Student Health nurse manager.
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